I use rackspace on 2 servers that I have used there for over 3 years. They are for mission crit projects, and yeah they are expensive. But, in 3 years never have I had downtime, and even when we integrated from RH8 to RHE this year they really made sure everything was ready for us.
If you do sign up, sign up using this link so I can make a little loot from it please
Rackspace SIgn Up