I was surprised by how much I liked it. I especially liked how the movie interprets Merlin.
You won't see any computer generated special effects, but the movie's use of real makeup, real pyrotechnics, and real, live stunt men was a refreshing difference between it and other recent action movies. Some worry that it contradicts history, but other than fudging some dates and inventing the myth of Cesar's sword, I didn't see anything unhistorical about it. The date fudging was only mildly bothersome, and without the mythical sword, there would be no story in the first place. It thought it was plausible and fairly well grounded in history. In any event, Arthurian legend has always lived in the margin between history and fiction, which is part of its appeal. There's also a hot heroine and lots of violent barbarians. What's not to like?