When comparing Tribler vs aria2, the Slant community recommends aria2 for most people. In the question“What are the best Torrent clients?” aria2 is ranked 4th while Tribler is ranked 12th.
Ranked in these QuestionsQuestion Ranking
Pro No website needed to find torrents
Tribler has a built-in, extendable search.
Pro Has a p2p search engine that can never be taken down
Pro Free and ad-less
Tribler is free and completely ad-less.
Pro Uses P2P onion routing to provide anonymity
Tribler covers basics such as Prioritization, Selective Downloading, DHT, PEX and Magnet URIs as well as Broadcatching 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 µTP data transfer protocol support. Even covers web seeding and embedded tracker. And it auto-updates.
Watch your videos while you download them.
Pro Free and open source
Pro Supports multiple download protocols
Has support for lots of download protocols including BitTorrent, Metalink, HTTP, HTTPS and FTP.
Pro Small memory footprint
Due to aria2 being a CLI only tool it uses very little memory.
Pro Remote control over simple standartized RPC
XML or JSON-based RPCs can be used to control aria2 remotely with both APIs completely documented. Simplest client that uploads torrent to be downloaded is 3 Python lines long (no 3rd-party libraries, only stdlib).
aria2c --help=#rpc to see more.
Pro Third parties offer a clean web interface
Some web interfaces consist of pure HTML+JS, no server-side needed (except aria2c of course). It uses the same RPC that can work even over WebSockets.
Con Highly questionable developer competence
On December 2014, Yawning Angel did a casual code analysis and found a plethora of Tor protocol flaws and implementation issues calling in question their general quality assurance practices and code quality.
Con Lacks IPv6 support
Con No super-seeding
Super-seeding is an algorithm used to allow downloaders become uploaders quicker. Tribler lacks support for this functionality.
Con No local peer discovery
Con Files can't be downloaded sequentially
Sequential downloading can be used to stream media files such as video and audio while the download is still in progress. Transmission requires waiting until the complete file is downloaded before it's ready for use.
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. Tribler lacks this functionality.
Con Lacks NAT traversal support
Con No UDP tracker transfer protocol support
Con No native graphical user interface
While there is a web-based GUI, there is no native interface.