I've been to and fro with TSO Host. The file access speeds (and CPU speed) of their cloud services were painful a few months back, to the point where it took several minutes to uncompress a Wordpress theme or 30 minutes plus to make a backup of a 1GB site, but I have to say I've been impressed of late. It takes probably a third of that time to do those tasks now - not as good as the usual cPanel hosting, but then it's much cheaper too.
It goes without saying that their support is strong and quick.
My only remaining complaint is that I'm not convinced that Google Apps DNS is working properly (several sites state an email address is not valid, though their support maintain its set up properly).