A good host will get back to you with in 1 hour. If they respond quickly, is the reply friendly, does it answer all your questions and is personal? If so you can move onto the next step. Go for a medium sizes web host and I guarantee they will provide more personal help and be more willing to assist you in your needs.
Take a look at
GTHost.com and
HostingSource.com dedicated servers.
Never experienced any downtime. They have superb reputation and you will have a wonderful experience with them.