Pretty much everything. Slow to load, slow to refresh, slow dialog boxes.

Other stuff on my system is quite fast.

The usual reason for slowness on OS X is one of the following:

1. Lack of HDD space (10%+ is benchmark to keep OS X's dynamic defrag happy) 2. Low memory - ST has to launch git & hg binaries and low memory affects those tasks especially 3. Running Mercurial on the App Store version on 10.8 - this is a little esoteric but it's down to Python precompilation and slight differences in versions. You can resolve that by using the system Mercurial instead of the embedded one for now.

It used to be rather slow for me, too. It got a lot faster with their 1.5 release, and (of course) ever since I did 'git gc' it also got a lot faster.