When comparing qBittorrent vs Deluge, the Slant community recommends qBittorrent for most people. In the question“What are the best Torrent clients?” qBittorrent is ranked 1st while Deluge is ranked 3rd. The most important reason people chose qBittorrent is:
qBittorrent is available as free, ad-less software licensed under GPL with source code available on [GitHub](https://github.com/qbittorrent/qBittorrent/). Being open source allows anyone to check if the software has no malicious code, is secure and respects privacy.
Specs
Ranked in these QuestionsQuestion Ranking
Pros
Pro Free, ad-less and open source
qBittorrent is available as free, ad-less software licensed under GPL with source code available on GitHub. Being open source allows anyone to check if the software has no malicious code, is secure and respects privacy.
Pro Lightweight
Pro Full-featured
qBittorrent covers basics such as Prioritization, Selective Downloading, DHT, PEX, LPD and Magnet URIs as well as Broadcatching, Sequential downloading and Search. It includes MSE/PE for security. It has graphical, web and command line interfaces. Has UPnP, NAT-PMP, NAT traversal for automatic router configuration. Has UDP tracker and µTP data transfer protocol support. Even covers Tracker Exchange, IPv6, web seeding, Embedded tracker, Super-seeding and proxy servers.
Pro Sequential downloading
Allows to download the first file of a series prior to the following items.
Pro Preload Magnet metadata
Obtain lists of files in Magnet before prompting the user for a download location.
Pro Auto torrent adding
Torrents can be automatically read from a folder.
Pro Enables streaming media while it's downloading
qBittorrent supports sequential downloading that allows users to download files in sequential order. That means that media such as video or audio can be streamed a the same way it can be with any other streaming service.
Pro Allows share ratio limiting
Can configure to what ratio (amount uploaded/amount uploaded) the torrent should be seeded. You can also configure on whether you want them to be paused or removed after this.
May also set this directly in the ~/.config/qBittorrent/qBittorrent.conf
:
[Preferences]
Bittorrent\MaxRatio=2.5
Bittorrent\MaxRatioAction=0 # 0=Pause, 1=Remove
Pro Super-seeding
Algorithm that helps downloaders to be able to become uploaders more quickly.
Pro In-Program torrent search via various search-engines
Uses python plugins made and maintained by users that can be found on the official websites.
Pro Can be used to create torrents (embedded tracker)
qBittorrent can be used to create a torrent to share large files/folders with other people.
Pro Good web interface
The remote API and web interface works well. There is headless version too (called qbittorrent-nox).
Pro RSS support
Add RSS feeds for automatic downloading. Apply filters to only download what you want.
Pro Has a command line interface and a daemon
Can be run on a headless Linux (for text-only mode from the command-line without requiring X11). The package is commonly named qbittorrent-nox (and it's officially supported by qBittorrent).
Pro Search engine plugins
What i love most about qbit is the "SEARCH" option thru major torrent-websites.
Pro IP filtering
IP filtering blocks set IP addresses. It's usually used to block communications with certain companies that are against p2p activity, etc.
Pro Tracker exchange
Makes it possible for BitTorrent peers to learn about new trackers for a swarm they have joined. Ideally ending up with every peer knowing about every tracker used for the torrent
Pro Tagging
qBittorrent now allows tagging individual torrents. So, besides Categorising torrents (ISO, Video, Podcasts, etc) you can tag torrents too (Jul, Aug, Sep or whatever).
Pro Quick and non-intrusive
Pro Functionality can be extended with a variety of plugins
As is, Deluge is very stripped down, but its functionality can be increased via plugins. As such Deluge can have only the functionality that is needed and skip any other reducing resource usage.
Pro Free, ad-less and open source
Deluge is free, ad-less and open source software licensed under GPL with source code available here. Being open source allows anyone to check if the software has no malicious code, is secure and respects privacy.
Pro Can encrypt traffic
MSE/PE or Message Stream Encryption/Protocol Encryption is BitTorrent traffic encryption method designed to improve privacy. It also attempts to make it harder to identify BitTorrent traffic by third parties such as ISPs that can choose to throttle it.
Pro Good web UI
Deluge has a web interfaces that can be used to remotely control torrents.
Pro Full-featured
Deluge covers basics such as Prioritization, Selective Downloading, DHT, PEX, LPD and Magnet URIs. It includes MSE/PE for security. It has graphical, web and command line interfaces. Has UPnP, NAT-PMP, NAT traversal for automatic router configuration. Has UDP tracker data transfer protocol support. Even covers IPv6 and proxy servers.
Pro Lightweight
Deluge weighs under 15MB.
Pro Has a command line interface and a daemon
Deluge can be run in text-only mode via the deluge-console
command. Requires first running the deluge daemon deluged
. Utilizing the deluge daemon deluged
allows remotely connecting to it, and using any front-end interface.
Pro Portable
µTorrent can be run without having to be installed. It can be put on an external storage device (such as a USB drive) and run directly from it. A portable version of Deluge can be downloaded from SourceForge.
Pro Neat and clean look
The GTK elements aren't the best looking in the world, but they are very tidy, minimal and easy on the eyes.
Pro Utorrent compatible
You can download using both clients µTorrent and Deluge on any supported operating system.
Cons
Con Has issues with large torrent numbers
Various issues occur with large torrent numbers (anywhere between 300 and 1000 torrents) including timestamp and file corruptions.
Con Consumes much RAM
It doesn't leave small footprint on your system.
Con Old UI
Looks a bit ugly.
Con Needs to be reinstalled from time to time
Sometimes it just stops downloading, the fix is uninstalling and installing again. It's a pain, but ends up working.
Con No mobile web UI
When accessing the web ui on a mobile device such as a phone, it uses the desktop interface.
Con Torrent downloads can freeze
Multiple people have reported that torrents stop downloading and stay in a "stalled" state indefinitely.
Con Search engine requires installing Python
Con No global sequential downloads toggle, yet...
Forcing you to toggle it individually everytime.
Con Can freeze in the background when exiting the program
Forcing you to kill the task in the sysmon.
Con Search engine does not function after version 4.1.5
Con WebUI version is slow when going into files tab
It's moving in slow motion when accessing the WebUI files tab of a seedbox with a phone.
Con Constant IO error
Con No built-in search engine
Built-in search engines allow finding torrents to download right from withing the torrent client. Deluge lacks such functionality.
Con No super-seeding support out of the box
Super-seeding is an algorithm used to allow downloaders become uploaders quicker. Deluge lacks support for this functionality out of the box. However, the ltconfig plugin can enable this setting: http://forum.deluge-torrent.org/viewtopic.php?f=9&t=42887.
Con Hasn't been updated in a while
As of writing of this, there has not been a new release in ~1.5 years.
Con Files can't be downloaded sequentially by default
Sequential downloading can be used to stream media files such as video and audio while the download is still in progress. By default, Deluge requires waiting until the complete file is downloaded before it's ready for use.
But it should be mentioned that there exists a plugin: https://github.com/JohnDoee/deluge-streaming for video streaming from Deluge.

Con Demon not lightweight as expected
While it has been improved a lot in the last years, when it's used in "headless" mode, the python demon still tends to use more resources than expected. It's noticeable especially on devices like the raspberry, and for instance, rtorrent and transmission use much less CPU.
Con Includes minor UI issues
Deluge has minor UI issues such as presenting "delete with data" as the most prominent button when removing a torrent from a list of downloads, or the way it resets its size when maximized from tray forcing a resize each time.
Con Does not preload magnet data
If a magnet URI is used there's no way to get information about contents or perform any kind of actions (such as selecting what to download) before the download has started.
Con No web seeding suport
Web seeding support allows downloading file parts from an HTTP source alongside the swarm. It's usually used for long-term seeding and easing some of the load on web hosts that supply direct downloads by offering a BitTorrent download as an alternative while still ensuring that the file is always available in its entirety regardless of the swarm. Deluge lacks this functionality.
Con Keeps Unwanted Files (Poor selective Download)
Deluge creates all the files even those that you marked "not download". Making your directories messy.
This is very bad when you want to create a drive specific for large files and you are unable to delete or move small and unwanted files, such as a video partition with large allocation unit.
[qbittorrent doesn't do that]
Con Doesn't shows all time uploaded and downloaded data
Con Can't "force start" downloads
There's no way to manually override settings for download queuing that's available in other torrent clients. For example, if there are 2 files in the download list and the software is configured to queue just one at a time there's no way to force a download of both without changing the settings. A workaround plugin can be found here.
Con Lacks µTP transfer protocol support
Con Naive search function
Searching for torrents or files within torrents is difficult because it relies on the user to input the exact title with the right index for each character.
Con CPU usage does not scale well with number of torrents
Deluge uses ~10% of one Core i7-2600 core with ~1700 torrents loaded, even if all the torrents are idle.
Con No tracker exchange
Tracker exchange functionality allows peers to exchange information about trackers of a given file. It is another way of ensuring that the file is downloaded from the optimal source. Deluge lacks this functionality.
Con No embedded tracker
An embedded tracker allows turning the client into a server offering an easy way of sharing files with others. Deluge lacks embedded tracker support so another method of sharing or different client has to be used to share files.
Con Doesn't seed
Con No built-in broadcatching support
Broadcatching is a method of automatically downloading content as soon as it's available. Broadcatching in BitTorrent clients is usually implemented via RSS. Deluge requires manually selecting each download by default. Fortunately, there are multiple plugins available that add this functionality with the possible caveat of plugins not having the same quality standard as the client itself.
