Depends on what your needs are. Unless you plan on seeding thousands of torrents they are all generally the same for simply downloading/uploading a sensible amount of files.

I vote Qbittorrent because there are good docker containers available that include vpn functionality (see binhex/qbittorentvpn) and it can handle quite a lot of torrents, but it does seem to have its limits. Can handle easily over 1k large sized torrents without any work but anything beyond that you probably need to make changes to the container and its resources to make it work properly. Qbittorrent also has a categorisation system which is handy for classifying downloading types and putting them in certain defined places.

I'm not aware of a solution to handle extremely large volumes of torrents seeding (lets say 10,000+ big torrents). I just seed the stuff I see as important (packs and BJJ stuff I think that is good).

I will put my 2c+tax in on this old discussion and say Qbittorrent for the win. I have been using it for over 20 years. When all the others were pay or full of ads or had one issue or another, for me, Qbit has been rock solid and 100% free, the real pirate way.

If you are using Utorrent you are on a sinking... sunken ship.

Jump on board Qbit and be a real pirate mate!