Woohoo! I moved from SmartGit to SourceTree on Mac quite a while back. I really like the user interface, the performance and the git-flow support.
SmartGit is an excellent product and I still highly recommend it when you need to support cross-platform users now with a common tool.
Now the folks at Atlassian have a new Windows client. It’s missing git-flow support which is a huge bummer. I look forward to this being added.