I strongly disagree with anyone who says WaW sucks.
If you grasp any understanding of WW2, or even more broad, the era it took place in, you will like it.
Personally, I loved the time period and the weapons, all the people these days that are into FPS games seem to favor ones that have modern weaponry.
It seems there shouldn't even have been a second modern warfare, it was made only a few years after the first...more like a large update of sorts. Doesn't seem like there's enough change between the two, however, I have yet to play MW2 so I may be totally wrong. I claim to know nothing, other than my opinion.
As for MOH, I played it on PS2 and original Playstation, I liked them personally. However, I would choose WaW over them anyday.