Great game overall, but everything following the E3 demonstration was a huge let down. The final level of Gears 1, minus Raam, was absolutely fantastic. It left such a good impression. The music, the high speed train, the variety of encounters, it was intense and awesome. The final segment leading up to the boss as well as the boss itself was really lame in Gears 2, however. Very disappointing.
Still, the rest of the last Act was plenty good. The scenery was fantastic (the best in the game, if you ask me) and the gameplay was mostly great (though that tiny crane bit was awkward).
Overall, I still think I prefer Gears 1. It left more of an impact on me back in 2006 and featured more a appealing setting (for me). Gears 2 is better in some ways but doesn't hit all of the same high notes.
I'm surprised that the ending for both games was so weak, though. I mean, in both cases, the ending just kind of came out of nowhere and had nothing to say. Both games had terrible final bosses, though at least the battle in Gears 1 was an actual fight (even if it was a lame one).
It was still a fantastic followup and one of the more memorable experiences of the year. I feel almost completely satisfied with it. Can't wait for more CO-OP and, perhaps, some multiplayer.