Prior versions of Transmission have been the best torrent program on the planet. There have been a few hiccups in the past, but usually by the time a .1 version comes out things are right again. The 0.8 series added a LOT of features, and they are nice, but reliability has gone for now. 0.80 was unusable, and 0.81 did seem to fix a lot of the issues but is still very buggy. The biggest problems are outright crashes, and mysterious freezes when attempting to add multiple torrents within a few minute time span.

Stick with the 0.7 series for now. This program is under fairly active development again, and I bet they will have the 0.8 series reliable within a month or two.