I don't know of any of those types of companies. But I use ManageMyBox and they're great. I've upgraded my server with them, and I've also had support requests answered in less than 4 hours time. The longest support request was when my server went down (the only time so far) and it took almost 6 hours to come back up. But that was on a weekend (a national holiday no less) so it took longer than usual.
Overall, I've been extremely happy with them. They're extremely helpful and extremely quick. So there's a 4th. ManageMyBox to me has been great. I can't complain too much.
I do know someone that works for LayeredTech. He set up my box on ManageMyBox secured it for me. Knows exactly what he's doing (30+ years experience), and it's been serving me well for a few months now. So they're another service to look at.
Hope that helps.