When comparing Transmission vs qBittorrent, the Slant community recommends qBittorrent for most people. In the question“What are the best Torrent clients?” qBittorrent is ranked 1st while Transmission is ranked 2nd. 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
Transmission is free, ad-less and open source software licensed under GPL with parts under MIT 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 Very minimalistic, straightforward design philosophy
Transmission is great for getting things done without looking too much under the hood. It still has advanced options, they're just tucked away from sight.
Pro Very lightweight
Transmission-gtk uses only 17 mb of RAM in idle state and 24 mb in download state.
Pro Native Mac, GTK+ and Qt interfaces provide seamless integration with OSX and Linux systems
Transmission works well on OSX and various distributions of Linux due to having interfaces natively developed for those operating systems instead of haphazardly ported.
The Mac interface is written in Objective-C, uses dock badges and Growl notifications while the GTK+ interface follows GNOME Human Interface Guidelines and has support for popup notifications, desktop sounds, and a system tray.
There's also an unofficial port of Transmission-Qt for Windows.
Pro Full-featured
Transmission covers basics such as Prioritization, Selective Downloading, DHT, PEX, LPD and Magnet URIs. It has graphical, web and command line interfaces. It includes MSE/PE for security. Has UPnP, NAT-PMP, NAT traversal for automatic router configuration. Has UDP tracker and µTP data transfer protocol support. Even covers IPv6, Web seeding and Local Peer Discovery. And it auto-updates.
Pro Has a command line interface and a daemon
Transmission can be used in text-only mode via transmission-cli
that includes a daemon (transmission-daemon
), a CLI and a web client (accessed on http://localhost:9091 by default).
Pro Works great on a seedbox with its web interface
Transmission has a web interfaces that can be used to remotely control torrents. It's great as a seedbox (a dedicated private server for uploading and downloading content) due to built-in webseed support.
Pro Pre-installed on multiple Linux distributions, including Ubuntu
For those who prefer Linux, the Ubuntu OS comes with Transmission already installed, so you can get your torrents up and running immediately.
Pro Headless software
Just put it on your server, SBC or even your old phone and you have your own torrent server.
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
Cons
Con No preload magnet metadata
Transmission is unable to preload magnet metadata.
Con If data is corrupted, torrent file has to be re-added
If you delete a file that belongs to (finished or not) torrent, torrent will remain in "corrupted data" state and only way to restore it (aside from restoring the actual data file) is to find the original file and re-add it.
Con No 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. Transmission requires manually selecting each download.
Con No super-seeding support
Super-seeding is an algorithm used to allow downloaders become uploaders quicker. Transmission lacks support for this functionality.

Con The app is hiding too much information
While the app is clearly going for minimalism, some users might feel that the default window that consists of just torrents and their progress bars might provide a bit too little information or functionality. For example, even accessing file lists requires opening up a separate window and navigating to a specific tab.
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. Transmission 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. Transmission lacks embedded tracker support so another method of sharing or different client has to be used to share files.
Con Written in Python, uses a lot of CPU on fast downloads
Apparently, the speed bottleneck is Python.
Con No built-in search engine
Built-in search engines allow finding torrents to download right from withing the torrent client. Transmission lacks such functionality.
Con No proxy server support
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
