This is a big surprise to me given my poor experience. I was on their (dv) — a VPS offering. Their customer service was really, really polite, but not fast (12-15h wait, on average). They never once helped me resolve my problems (they tried, but they seemed about as clued in as I was, which was close but not enough). I upgraded to a $150/month option and my site was still thrashing with 15 sec load times. I left them for my current host, where I have the same Apache and MySQL settings, pay $60/month, and have never experienced the same problems again despite hitting peak traffic season a few days ago.
My point is not to rant, but instead to suggest that these folks should seriously consider doing some internal improvement if they hope to retain the customers that they will soon acquire.
I had a very similar experience to the original poster, the main difference being that we were using their top end nitro package. We left after we realized that for the same money we could actually get managed hosting.
We moved to Neospire, and I've never looked back. I've never had to wait longer then 5 minutes on a support call, and their support has been fantastic. They actually called me when my server load was high and assisted me in tuning the server.
To be fair to MT, they are very clear about their service -- "we'll rent you a box, but don't ask for admin support."
I hope they "acquire" shared hosting that doesn't go down every 8 minutes. They advertise robustness ("designed to handle large spikes of traffic with ease") but then some networking problem on their end, unrelated to traffic, causes all your sites to go offline anyway.
Of course, I'm just being snarky — every host has their share of problems, and the customer service with MT is the best I've ever experienced. This is good news – they do some cool stuff: http://mediatemple.net/labs/ (virtualized Xserve hosting? Neat.)
I have few sites with MT that I have been lazy about moving from them. I was absolutely sick of constant downtime and overall speed of their systems and the recent massive security incident (they changed database password of all users second time in the last 4 months for precaution).
In their defense, they recently improved their stability and speed with their last hardware/architecture upgrades (at least for now it seems).
I used a Media Temple (gs) server as a testing/staging server for a project I worked on last year. The MySQL server was comically slow (I'm talking 5-10+ second response times), and would simply stop responding multiple times a day. Support acknowledged a problem but nothing ever got fixed. I eventually moved over to Linode, where response times were near-instant and downtime was never a problem.
During that same period, I started using email hosted on my own domain through my Media Temple account, and would see straight up email downtime 1-2 times a week (as I remember there were periods were emails were dropped without notification), and usually saw terrible performance when the server was running. Since then I've used Google Apps and Fastmail, and have had absolutely no issues with either.
It's possible that I just had extremely bad luck and made some errors on my end, and I know some smart people who seem to use Media Temple without any problems, but I've been burned way too many times by them to even consider using them for something in the future.
I had several sites on Media Temple's "grid" service before cloud options were in vogue. The reliability and performance were terrible. Media Temple blamed Expression Engine CMS and Mint tracking scripts, which seemed odd given that they are quite popular and well written. I moved those same sites to Joyent and have never been disappointed.
My point is not to rant, but instead to suggest that these folks should seriously consider doing some internal improvement if they hope to retain the customers that they will soon acquire.