If you are eager to continue trying out BitTorrent (but don't want to downgrade from 8.5), and you are tired of BitTorrent clients that are huge and take up lots of system resources, this might just interest you.
I recently saw a story about a new BitTorrent client (with support for creating torrents!) called µTorrent (or uTorrent) on Digg. It's tiny – less than 100K – and doesn't even require an installer. Simply download it to somewhere run it, and that's it. The latest version at time of writing is 1.1.4, and it seems to work really well.
I will probably use Opera for my daily BitTorrent needs (one of the sites I check out regularly to stay updated on what's going on in the gaming world is File Rush), but people with advanced needs, and who aren't easily put off by an advanced BitTorrent client with lots of options, should really give uTorrent a try.