I switched to gitextensions, sourcetree had so many bugs that it was getting on my nerves. Gitextensions has a similar layout, it also has the history view. It's not prefect (recently they removed the dark theme because they upgraded some dependency and it didn't work anymore) but it's the best alternative I've found
Tower is pretty nice for mac user too. I paid for it for a few versions back when I was coding full time. Now I just stuck to source tree for occasional freelance and personal projects.