I switched from a host that was constantly getting hacked and making server upgrades without notifying me or other customers. Dreamhost is great for the single reason that they almost always give prior warning before doing any updates or upgrades to servers. Plus, their customer support is usually very quick. In most cases I get a response within 45 minutes. My old host would take days sometimes. I believe I still have some open support tickets with my old host, which is sad, since I closed my account a few months ago.

Overall Dreamhost is amazing. Good prices, quick and intelligent support, and a good amount of control over the servers I am hosting on. I give them a 10 all around. I've seen a little bit of downtime here and there, but I've always have fair warning.