Be careful when you move to PS. It maybe very difficult to go back.
Dreamhost has this algorithm that allocate idle memory for dhapache processes. At first I thought it was stupid. But then I see the genius behind it.
If memory is idle, why not use it? If it's idle, it'll be completely useless. But if it's used, it can improve your sites' performance a little bit. Of course, the memory is way over allocated, but only when there are plenty of idle memory that's otherwise unused anyway.
However, the processes make it looks like you're using too much memory and a techie can simply disallow you to go back based on that.
Moreover, unlike 60 minutes CPU time, Dreamhost doesn't have a clear policy on allowable memory usage in shared server.
It happened to me.
At first I thought that I should move to PS and fix my stuff and go back. That way, if I create a bug in the process, I don't disturb others. Well, I wouldn't have found my bug if I didn't go to PS. But the fact that I couldn't go back make me very sad.
If dreamhost shared isn't that good, I'll probably just increase my hostgator purchase. Dreamhost shared is so good. So, I got into a heated argument with the techie, and now he's very mad at me.
-ex very happy shared hosting customer