When I was having trouble with DreamHost a few days ago, I signed up for a Grid Server account at Media Temple to try it out. After trying it, I decided to close my Media Temple account and stay with DreamHost.
I created a mirror of this site (which you can still see here until the end of the month), and I didn’t find it to be any faster than DreamHost. I also find that DreamHost’s control panel is a lot nicer.
I also prefer how DreamHost handles multiple domains. With DreamHost, I can create completely separate FTP/SSH accounts for each domain. Media Temple, on the other hand, uses a primary domain with other domains added as alternate domains, unless you purchase another IP address at extra cost. All of the domains appear in a domain subdirectory in a single FTP account, so there’s less separation between domains.