SublimeGit is fantastic. Incremental find (I think it's Ctrl+D) is like multicursor, but it selects the next occurrence of a string, so the cursors don't have to be on adjacent lines. It's been so long since I've used TextMate that I don't remember all the differences, but those two alone are worth switching for.

I also have SidebarEnhancements, Calculate, Alignment, EditorConfig, and Default File Type installed. None of them make a major impact, but they all make the experience a tad nicer.