Not played any Saints Row games, so I can't comment on those.
MW3 (as per usual) - has a good SP campaign to it and I really like the co-op and survival modes to it. Would never even attempt to spend 5mins online with it though - I just hate the way COD plays online.
BF3 - so, so SP campaign, but truly epic online experience. It's not flawless, but works very well when you have a couple of mates on there using TeamSpeak or something similar. If a couple of issues were addressed in the core game as I've mentioned before (unlimited ammo on vehicles, self-repair of vehicles and the lack of decent AA) - BF3 would be pretty much peerless online, imo.
D.