BF-42 has great MP if your team are not a bunch of n00bs or assholes, but it has crap SP (basically MP with dumb AIs)
of course if you get in a server with a bunch of n00bs then MP sucks (get the plane get the plane, shit someone wrecked it, get the tank, get the tank, damn someone rammed a jeep into it, etc.)

MOHAA has really immersive SP and the MP is pretty good, especially on one of the better user-made maps.