Currently Does NOT Work Over Dial-Up!
Turbine is aware of the issue, and has offered a partial-fix patch this past week, but if (like me) you live in a rural area and are forced to play over dial-up, you need to know that teaming and questing with others in DDO can regularly lock your character to a standstill when more than a couple of enemies appear on-screen.
Check out the DDO Tech Forums -- the problem is discussed there, and Turbine (again, as of this writing) is advising dial-up users to avoid "heavily-populated" quests.
In my experience, even out of questing mode, the game lag routinely brought my dial-up to a standstill.
I'm not saying don't buy the game; I'm saying, do your research on the DDO forums before you buy. make sure that the problem is fixed by the time you buy if you're a dial-up user!
For non-dialup users, I have to say that the Ofiicial Review here pretty much sums up the game accurately. It has a very specific style of play -- if you like that style, you'll love the game. If not, you won't.