The private trackers I know only recommend two clients, Azureus and µTorrent, so I'm sure µTorrent doesn't cheat, otherwise it would be banned.
µTorrent is my main recommendation. It never failed to me, even with a bunch of torrents going at the same time. Plus it has some other niceties that may be interesting to you, like the RSS Downloader, indispensable for certain "recursive" jobs :-P
The other client worth recommending is Halite, by DC's own Eóin. It has less bells and whistles, but it retains most of the functionality, including torrent stats
Maybe Deluge might catch your eye as well, although it looked like crap under Windows last time I used it. Azureus is bloated to no end, with tons of things you probably won't need. Plus it's written in Java. Opera would be the ultimate no frills torrent client, but I don't know how it performs with more than one torrent being downloaded. Finally, there are a few extensions for Firefox that add BitTorrent support, as some download managers that support the protocol, like FlashGet or Free Download Manager.
And there's no much else, frankly, the market for pure BitTorrent clients in Windows is a small one, most clients have not been updated in years, or have serious problems, either they cheat or they are stuffed with spyware.