I went to the Mr. O in 2008- the year Dexter Jackson won. While it was a great experience and something that I always wanted to see, I wouldn't go again.
The tickets were very expensive- $160 for the pre-judging, $212 for the finals. And while they were 'decent' seats and the best available when I booked I was still quite a ways from the stage and the view, even with binoculars, was not great. If you're really interested in seeing the competition, watch it on Bodybuilding.com or buy the dvd.
The best part of the Olympia weekend for me was the expo where you can get up close & personal with some of the athletes. I got to meet and chat with Markus Ruhl and Lou Ferrigno among others.