I agree, this movie is in the grand (present) tradition of Hollywood: lots of flash and little substance. In the genre, District 9 is far more entertaining (at least it's not predictable - be honest, now!) and believable. Star Trek was a welcoma and effective reboot, but beyond Trekkies, no outstanding selling points. Haven't seen Moon (haven't even heard about it), but I'll try to track it down.
A visual masterpiece, especially in 3-D. However, that doesn't make up for the fact that I could have eaten some alphabet soup and crapped a better screenplay. The dialogue goes from lame to cheesy and the acting is completely flat. Basically, aside from the visual, Cameron didn't even try.
For a lover of movies, this film is a disappointment. I think of it as an excellent guitar solo. It can dazzle an audience, but when it's done, you realize there really is no substance to it.
It should go without saying that this is simply my opinion. My friend watched it (not in 3-D) and loved it. He wanted to go right back in the theater and see it again. Essentially, I'm not telling anyone not to like it. If you enjoy it, great. Movies should bring entertainment and this one seems to do that for many people.
Again, IMHO... best alien movie of the year: District 9. Best space movie of the year: toss up between Star Trek and Moon.