I have been a loyal Utorrent user for 15 years, but it has too many problems - including crashes, freezes, and files that lose their association with their torrent. I have finally given up on Utorrent.

I tried every torrent client out there, and Qbittorrent's latest version is close to being perfect. It has a few very minor problems which are nothing compared to the massive problems of Utorrent.
It seems like Utorrent's developers have given up trying to fix their problems. People don't even bother to post in the Utorrent forums anymore.

Also, there is a genuine 64 bit version of Qbittorrent - which is able to utilize far more memory.