I'd wait it out for a week or so and check out the reviews first and some gameplay vids. You might get a taste of how it is.
Also, get the demo of Cod2 and play it on your pc; see if you like it.
PD0 is going to be aimed at a great multiplayer experience with fanatic shooting and running around. Think along the lines of Timesplitters: Future perfect.
I'm gonna wait it out for a while and see how it goes. I really want Oblivion, but I don't know which second game to get to play with my brother. I'm probably gonna end up getting PD0 because its a pick-up-and-play and I'll be playing Oblivion for most of the time anyways. PD0 migh just steal more hours away from me that I might think, though.
Like I said, just wait for a PD0 review and, while you're at it, play some Cod2 demo.