I use TotalFinder, but it is quite unstable in my experience. I probably restart it weekly, just due to some drag and drop nonsense that it didn't know how to handle. Don't get me wrong: I really like TotalFinder, but the stability is improving too slowly to make me really happy with it.

The early versions were crashing every few folders, but it's fairly stable now, with the occasional graphic lag between converting from Finder to tabbed Finder on boot.