For a free control panel interface for your servers to allow users to manage their own space or even for you to mange everything you can't go wrong. I will admit it needs a little work and I hope to be part of the solution.
Horrible installation process, 1/2 the steps aren't automated, spending hours wading through trying to make to make it work. Simple unusable. Oh, and did I mention you have to pay just to get instructions? Yeah, no, sorry, crap software.
Great, could use a better web ui though