After reading this and looking at CornerStone 2.0 and Versions, Corner Stone won on just the simplicity of their file compare.
With versions I have to download or install XCode (or something else). Cornerstone had it built in, and for my tastes the Cornerstones file compare is the best I've seen for a casual user. It's just immediately clear what was added and deleted.
I haven't tried the branch and merge but it seems Cornerstone has made that a big push.
