I loved Ocean's Eleven. It was interesting, humorous, and fun to watch. It was well-written, well-filmed, well-acted, and well-edited.
Let me warn you. This review contains spoilers. But let me warn you further: you absolutely do not want to see this movie. Trust me on this. It's my duty to convince you not to see this movie. Ever. It's not even worth watching for comedy value. And for that reason alone, this movie is worse than Battlefield Earth.
The movie is about 125 minutes long. Of those, about 110 minutes are spent in montages. It's simply a huge sequence of montages with occasional dialogue inserted for variety. But the montages aren't interesting - they don't advance the "plot", they don't develop characters, and they don't inform us of anything. They just waste time or show off strange camera angles. Most of them simply consist of each of the 12 characters taking a very long time to look at each other.
The movie starts with a montage of Benedict magically showing up in front of the 12 original heist members, one by one, to their surprise. Immediately afterward, there's a big meeting in which the 12 agree to pay Benedict back all of the money they stole in the first movie. Nobody fights it or questions it, and they all have a big meeting where they decide that they need to go steal some things in Amsterdam to make enough money to pay Benedict.
They all fly to Amsterdam and try to steal something. But we don't actually see the theft when it happens. We see a brief summary showing what "really" happened later, a technique employed by the first movie... once. In Twelve, they used this about 8 times. Nothing you see makes any sense at all until a while later, when they give a 10-second overview of what really happened. This time, it's not interesting, it's just frustrating and doesn't make sense.
They first tried to steal a stock certificate, but were beaten by a French guy, who becomes their new enemy. His motivation is that at a party, a master thief didn't say that he was the best thief in the world when the first movie's heist was introduced in a conversation. The French guy wants Ocean to say, "You're better than us." The remainder of the movie is based on this, and Benedict's magical detective skills are forgotten (until they're explained in a 10-second clip at the end, like everything else, long after you've stopped caring about it).
The movie really becomes ridiculous after this.
Then, in a "fun" plot twist, we find out that the French guy actually stole a replica placed there by Ocean's team, and they had actually stolen the real egg by switching backpacks with someone on a train a week earlier. So the entire second half of the movie was completely unnecessary.