I just recently watched Spamalot. I think I probably watched a couple of Monty Python movies in my life, and wasn't privvy to the storyline. Anyway, this was okay. Clay Aiken plays Sir Robin, and there were some lines relevant to American Idol and ex-governor Spitzer to make it more current. The set design wasn't as sophisticated as some of the other musicals and Broadway shows I've watched, and the atmosphere was like watching a high-school play because the humor appealed to a grand group of high schoolers (sitting next to us) that were hee-hawing at every boob and camel-toe joke.
But in the end, my overall opinion was that I like it, probably because of the "Find Your Grail" medley, some snarky bits, and it's originality. I would definitely watch this before seeing Wicked, and/or KA. I watched this after, so my expectations were higher.