I wonder if this is a general Media Temple thing. I have a few small sites using Drupal on MT and the response times vary widely. I thought it was because of Drupal itself (I never use it; client decision) but maybe it's just MT, which I've found to be basically horrible overall.
Sorry to hear about your bad experience so far. This would usually be the case due to different configurations between the sites, but if they are all the same uniform configuration we'd be happy to take a look for you. Please let me know if you have a support request open already. Finally, what in particular have you found horrible, and what would you like to see us fix the most?
