Just got through the plane sequence. Holy wow, so cool, maybe the coolest thing set piece I've ever played.
The combat though can just be so frustrating. There were times when I would die, and die, and die, from so many enemies being thrown at you, and snipers high up who would one hit kill you. On top of that guys constantly flanking you with shotguns. Sure, I get challenge, but this just wasn't fun for me. Maybe it is for other people. I've enjoyed difficult games like Far Cry 2, Halo series, the previous Uncharted games, but these scenarios felt like luck if I passed them a lot of the time, rather than me learning how to be better at the game.
Some of the platforming stuff can be frustrating as well. There are a number of times where I can't figure out where to jump, so I just jump in the general direction the game is pointing me and I magically sticky into grabbing a ladder or a ledge. Also, there were a lot of dead Drakes when I was playing through some of the chase sequences. Sounds like I had more trouble than others, but dying three or four times in those sequences really takes the cool out of it.
Having said that, through all of my issues, still having a lot of fun playing the game overall and will push through and complete it. Perhaps the main problem I have with Uncharted 3 is that Uncharted 2 was just so good.