I was a huge fan of sourcetree until the release of 1.9 and it was the only GUI that I've used instead of the cli for basic things, but the UI changes since then have been terrible. Far too much wasted whitespace and really odd decisions, like placing checkbox choices within a drop down menu (ignore commit hooks, amend last commit, etc.). Alas, 2.0 doesn't do anything to fix these issues, so 1.8 remains.

I believe padding is becoming ubiquitous in UI design. I see this on SourceTree and GNOME for that matter. Lots of white space that serve no purpose in desktop UIs.

Agreed. I still use it for more complex operations that are just a pain in the CLI, but the interface has really gone downhill over the past year.