I also just recently picked this game up(about 3 days ago.) I have really only played multiplayer, and i find this game very enjoyable and challenging. Graw has unique gameplay that I've only seen before in America's Army (not very fun imo,) I enjoy the tactical strategies that are present not only in single player like most first person shooters but also multiplayer where I can tell some "tactical" shooters fall behind.
One of my only gripes is that there is no in game voice communication(correct me if i'm wrong.) Yes I use teamspeak but I've never thought using a third party program should be a necessity(and voice IS a necessity.) I have found a server that I will most likly play on from now on, the name thats coming to mind is BDA (I'll edit when I find out what it really is.) Anyway they all seem friendly and are active on teamspeak.
Thats all I have to say, See you in game!