I can tell that Bungie put a lot of heart, soul, work, and dedication into this game. I love how innovative and interactive it is, I like that they push the envelope of first person shooters to a degree.
The only gripe that I have is that you can't communicate as well as I would like but that is small potatoes if anything. I could say that the competitive mode is quite difficult but I've always sucked in the whole online shooter category and I love it none the less.