I haven't used them personally, but from what I hear, they aren't terrible. Not great but not bad either. They apparently are best if you really know your way around a linux server, as apparently they are terrible at setting them up. Also, you have to make sure you specify proper partitioning for it, since apparently UCG knows nothing about doing it properly.
All in all, I'm sure it's fine for a personal or small business site. If you're looking to try them out, I believe you can get one of their $49 offers and upgrade it later to a $99.
