Alright. So I've played the 360 at my friends house. I must say, I am impressed.
I'm not talking about just the games, but the whole system. It felt so clean and sophisticated. For example, when you hold down the "X" logo in the center of the controler, it flawlessly searches for controllers and whether to hook up to the number one spot. Then it signifies it's spot with a quatere of the circle being lit up. It was brilliantly intuitive. The whole system is like that. The controller is VERY comfortable. The addition of shoulder buttons and lack of white and black buttons is a major plus. That's about it though. Apart from that, it's just an S "+."
Now, about the games. I only played Call of Duty. The first thing you'll notice about the game is the textures. The textures are definitely impressive, but sadly that's reallly the only thing going for it graphically. The textures basically accounted for everything "cool" in the game. I liked how enemies were hard to see due to high detail. Also, the players guns and jackets are nice. That's about it though. I guess some structural modeling was well-done, but again....strictly speaking about graphics, that's it. I was dissapointed about all the enemy charachters looking exactly the same. I was expecting some diversity (even goldeneye and PD had diversity).
One thing that was impressive was the immersion factor. It seemed like a SH!TLOAD of things were going on. There's a bunch of visual and audio distractions. Actually, the most impressive thing about the entire game was the audio. It felt nuts. I heard rifles blazing and I could tell if it was up-close or far away, behind me or in front of me. It was great. Honestly though, textures and audio can only do so much. As soon as you get past the "wow, this is crazy" aspect, it feels like all the rest of the games made this gen. And even more so, it felt like I was doing the same thing over and over again (however, it is a war game so i'll let it slide).
All in all, I had fun (though the game was more rinse and repeat then I would of liked). I definitely wouldn't pay 400, or even 300 for it. I had much higher hopes only considering the graphics for next gen games. Now I'm even more hyped towards REV gameplay possibilities. As a core system though (menu and all), the Xbox 360 nails it.