The graphics (whether up or down a notch) are very similar/close to CoD 4, which looks good and runs well. The game plays pretty well online. There are a few bugs that some small patches could clear up and I am sure that they will. Some of the guns are somewhat annoying, but in their defense it is WWII and not modern so the weapons should be different and actually should be quite worse (not that I am really going to consider and CoD realistic, but you know where I am coming from).
The only complaint that I have is with the bolt actions being a 2 shot kill in the chest. It really really bothers me, but oh well I suppose. That and the sounds are inconsistent and not that great. Those are 2 relatively minor complaints imo. If CoD 4 is a 9 then I would say that CoD 5 is probably around an 8.7 on the MP side. If you are more of a WWII fan then it may actually be a 9 or 9.2 for you just as it is for my roommate who hates CoD 4, but loves 5. To each their own, but I think the game is actually worthy of the CoD title this time around (unlike CoD 3), I applaud their effort and recommend the game.
Also know that unlike CoD 4, the PC version has prestige mode and if you don't use xfire then the in game friends list could be helpful. You also now have 65 levels instead of 55, you get more points (8, 6, 2) for amount of damage done on an assist instead of just 2 and after a certain level of prestige levels hit you are able to unlock more custom slots leading up to a total of 10 custom loadout slots.
Best,
3Ball