Well after two fails of this exam (and horrible Prometric testing experiences), I tested with VUE and passed with a 740. As many have said, know your DNS and RRAS stuff forwards and backwards. In hindsight, I probably failed the first two times due to over confidence. I found all the MS exams that I had taken to this point to be painfully easy (including the 290), and I suppose that I had an expectation that 291 would be really simple too. This is not the case. I have 10 years in IT and found the exam challenging each time I took it.
The horrible testing experiences with Prometric probably don't have anything to do with the fact tht I failed the first two times, but I needed to mention this nonetheless. I think it's deplorable that Microsoft is creating another monopoly in the fact that you have a single choice for test delivery when you need to obtain a MS certification. In Oregon there are very few (four) Prometric test centers and their hours are limited at two of them as they are community colleges.
With VUE, there are twice that amount and one of them is an actual Pearson corporate test center. The security is crazy high, but the quality of the test experience is bar none the best I have had. This is because they have 19" LCD's, up-to-date PC's, modern input devices (optical mice and ergonomic keyboards), and an experienced proctor who is always available if you have problems during an exam.
So let me have my moment of glory now...
YAY...I'm a MCSA!!!!