The game seems quite a bit quieter than Halo 3 campaign, probably because there isn't as much radio chatter. It certainly makes running around the city as the rookie interesting.
For me I picked the game up on 9/22 and have been trying to get through the campaign on normal (but I keep getting interrupted by friends who want to do a co-op campaign or firefight, and I'm one of those people who like to do a lot of exploring and try to find all of the hidden stuff). I like the silenced weapons, and they are only good as long as you kill your target with the first shot or two, if you take any more shots than that at a target all of the others turn and start coming after you.
Firefight is a lot of fun, I happened to be at the San Diego Comic-con this year and had a chance to play the game there, I enjoyed it then and still enjoy it now.
Now, I just need to finish all of the achievements (not because I want the recon armor, but because I enjoy the challenges that the achievements bring to each game).
One thing that I don't like about the multi-player disc is that you can't just download and install the new maps to your current Halo 3, instead you just have to use that disc all the time to be able to access them. Which isn't a problem if you just play multi-player all the time, but I like to do co-op as well. Anyways, it's been fun playing, I just need to find a good 4-6 hour block of time where I can just sit and enjoy the game without being bothered (weeknights are difficult since I don't have much time to split up after work).
Also, I should note that I do enjoy playing multi-player a lot, it's just that when I first get a game I like to run through the single player parts so I can get used to it and enjoy whatever story line is associated with it, otherwise when I try to run campaign with other people they just rush through all the story line videos and you don't get to understand what is going on. After I finish that, then I'm all over multi-player.
