One of the big reasons I found AUD easiest was that I felt absolutely no time pressure. I took a bathroom break, double checked every MCQ and SIM, and left with over an hour to spare. I didn't think BEC was overly hard, but I was wiped (4th exam in 6 weeks) and had a lot of calculations so time was much more of an issue. Plus my writing questions weren't overly difficult, but 2 of them required longer answers than I'd expected. It definitely was much easier than FAR or REG, though.
FAR 4/1/11 - 89
AUD 4/15/11 - 85
REG 4/29/11 - 80
BEC 5/13/11 - 85