If you're at all tolerant of U2's music, it's really worth seeing. It's not gimmicky at all like most 3D movies are...the 3D is mostly used for depth, since they filmed it in South America in their ridiculously huge soccer ('scuse me....football) stadiums, but it's really amazing. I was kind of underwhelmed at the setlist (they had to cut a 2 hr and 15 minute show down to about 85 minutes, but made some really predictable choices that made the show flow differently than it did at the actual concerts) but the performances are great and visually it's one of the coolest documents i've ever seen of a concert.
Most importantly...it's the first U2 concert in 10 years that wasn't ruined by Hamish Hamilton's ADD-on-crack directing skills. Highly recommended.