It's kind of like asking how the rice is at a Chinese restaurant. I like rice just fine, but I go to the Chinese restaurant for the kung-pao chicken not the rice and you definitely don't play battlefield for the single player.
I've finished two or three missions on normal difficulty and It's fine in a steamed-white-rice kind of way.
So far Im liking the campaign. Just beat the jet mission, where you bomb the airfield. so not far into it, but considering how short SP games are theses days, Im sure Im nearing the halfway mark within another hour and a half. lol