No, they are not overselling at all - in fact, anyone offering a VPS can't really oversell all that much as you have to maintain a minimum guarantee of CPU and RAM. Diskspace, well, thats a different story. However, they truely are there 24x7 (I've called them at 4 in the morning before) and they're always ready to help. One thing that I'm not so happy about (and I guess I'm just used to instantaneous replies) is that it takes a few hours to get a response back from their team initially - but once you do get the initial reply, it's all smooth sailing from there. Of course, if it's an urgent issue - you can always call them up 🙂. Some techs even list their IM handles in their e-mail sigs so you can get a hold of them even without opening up a ticket or calling them up 🙂
-- Jonathan