I work a lot for a client who has several sites hosted by MediaTemple on a GridServer configuration. Most of the time, that results into unusually slow EE sites (the same site hosted somewhere else would be much quicker, so EE’s in the clear, here). Maybe due to MT being in the US and my client and me being in Europe, maybe something else, but my conclusion so far is that GS and EE isn’t a very good combination.
Does anyone have any experience with MT and their Dedicated Virtual servers? My client is considering moving to such a configuration if it improves performance.