My girlfriend and I went to see it last night, and what we saw was really good. I just have no idea how it ends because just as Cate Blanchet's character is vaporized, the movie screwed up. They restarted it two more times, but the picture always cut off and went to a pink screen at that exact same moment. So they sent us away and told us we could use our stubs to come back for free.
I'm trying to gauge public opinion while avoiding any spoilers about the last however many minutes were left in the film. As for me, I liked it. I, too, was a bit dubious over the whole Tarzan thing. How many George Lucas movies can have Tarzan moments in them anyway? Now we have Jedi, Sith, and Crystal Skull with Tarzan bits in them. I also agree that the music wasn't too terribly impressive. The whole college town chase sounded just like the storming of Naboo at the end of Phantom Menace. But those "big damn ants" creeped me the hell out, and it's great to see Indy back in action. I didn't even think the whole alien plotline was bad, and that was what worried me the most going into it.