qBittorrent is a near-perfect GUI BitTorrent client for GNU/Linux, *BSD, Mac and Windows computers systems. It is fairly light-weight and very efficient. It has all the basic features one would expect from a modern BitTorrent client and it has also got some useful features most other BitTorrent clients do not have such as a multi-source search function and RSS feed subscriptions.
Features and usability
qBittorrent is really easy to use. Adding a torrent to download is as simple as clicking a button and choosing the file. Creating torrents is also easy and strait-forward. Choose
Torrent Creator from it's menu, choose a file or folder to share, optionally add trackers and click
Create torrent. It's that easy.
qBittorrent's biggest advantage over similar software is it's built-in search function. It may be disabled by default, enabling it is a matter of choosing it from the menu
Search engine. This function relies on having "Search plugins" installed. Some are bundled with the default installation, others have to be manually installed. This feature, when the right search-plugins installed, makes qBittorrent a one-stop shop for everything publicly available which you may want to acquire. It eliminates the need to open a browser except when content from private trackers is required and desired.
The RSS feed reader and downloader is another great feature qBittorrent has which isn't there in most clients. It is possible to filter RSS feeds for keywords and automatically download new torrents matching a set of rules. This is very handy for downloading specific spins of new releases of Linux distributions when they become available. It is, for example, possible to subscribe to the RSS feed for fortorrents.fedoraproject.org and only download new releases of Xfce spins.
qBittorrent has all the other basic features one would expect from such a program such as DHT support, trackerless torrents, torrent queuing and prioritization, selective download of files in multi-file torrents, peer banning, private trackers and private torrents, uPnP for port-forwarding and system tray integration.
qBittorrent can be ran in a "headless" mode where it demonizes and starts a web service which can be used to control it. This is handy for running it on a limited server which is on 24/7.
qBittorrent has bugs and there appears to be plenty of them in the v4.1.x series - specially on Windows. The number of open issues is very high.
qBittorrent versions in the 4.1.x series crashing appear to be specially common for users who are seeding a very large amount of torrent files with a high number of peers.
qBittorrent v4.2.0 does not appear to be anywhere near as crash-prone, but it may only appear that way. There is difference between seeding two Linux ISOs and seeding hundreds of torrents with thousands of peers. Your mileage may vary.
qBittorrent is written in C++ using the libtorrent-rasterbar library. Version 4.1.x uses libtorrent-rasterbar 1.x, 4.2.x can use both libtorrent-rasterbar 1.x and 2.x. qBittorrent's graphical interface is built using Qt and the applications code-base is heavily leveraging the Boost library.
Verdict and Conclusion
qBittorrent is a really nice and user-friendly client and it's search-function makes it real easy to find new Linux ISOs to download. However, the reports of it crashing are real and that is a real problem for quite a few of those who have tried to use this client for their fresh Linux ISO needs. If the version your linux distribution ships in it's repositories is stable for your needs then it's a great client. If you need to seed hundreds of Linux ISOs to thousands of people then you may find that it's just not solid enough for such purposes.