I'm having all sorts of reliability issues with 1.6.3 (which is the least unstable 1.6.x until now).
Things like this make working with it really unpleasant as they are intermittent and I've spend more than an hour trying to find reproducible cases.
- during operations the focus gets lots, especially when checking in and copying change-set descriptions: the edit Windows don't get focus.
- during checkin, files appear from the staging area, and when you start 1.5.2 they are just there. This happens most frequently when you have changed files after you put some of them into the staging area.
1.5.2 was reliable, even in the lack of support for certain things or things that didn't work well: it would either work all the time, or fail all the time.
1.6.x looks more polished than 1.6.x, but is harder to work with (as some operations are now hidden behind menus).
But the thing that got me reverting to 1.5.2 is that 1.6.x is unreliable. Things work most of the time, then just fail.
I'm not sure yet, but the impression so far is that 1.6.x also uses more memory than 1.5.x, I think a lot more. I won't try for a while: I will watch the summary panel becoming less red before updating again.