Just passed 290 last week. (yay, me!) I won't go into super specifics of the questions because people get antsy about that. But they REALLY expect you to read for content on these things. For example, I'm sure you're familiar with the "user got account locked" question. You can do it in your sleep. Reenable account, reset password to "blank" or whatever, check the "user must reset password" at login. I got a simulation that asked "give the user a password of password, do not change any other policies." And the question said "do what we told you, no more." So hmm! Best practice is to hit the reset button. In real life that's what I'd do. But that's not what the question asked for. So I left it unchecked. Dunno if I got that one right or wrong but I passed the test so that's all that matters.
I did see some of the "brain dump" material for 290 but they're really outdated. The microsoft books are outdated for that matter, too. The sample questions from the book are really not like from the test either.
More important than whether or not you did a brain dump or just read the books, you need to be doing this stuff on practice systems, not just reading about the work but doing it. The reason to look down on a person who passes with a brain dump is they have the cert without knowing the material and makes certified people look no better than random yabobs on the street. Well, you can wind up with legitimate only-studied-the-book paper MCSE's just as easily without practicing this crap, even after you got the cert. I sat the class two years ago, then got hired in an IT job that isn't directly sysadmin and didn't have time to finish the exams. Going back and doing it now and it's amazing how much stuff I'm fuzzy on or plain can't remember, stuff I know I knew.
Well, on to 291. Yikes!