I played about 2 hours of SP and about 30 minutes of MP. I'm amazed at how good it looks on my shitty hardware. I have a gtx780 running at 1440p and it was very detailed and smooth, pretty much like how Battlefront 2 runs.
The SP gameplay, on the other had, is garbage. There wasn't a single moment where I didn't feel like I was on rails, more or less. You are just guided through scripted shit... if you don't figure it out the first time, you probably will the second.
The other weird thing is that when you die, they show the name of the person that was just killed. I thought that was a great idea until the cutscenes reverted back to the character that died at the start of the scenario. Arma 3, this is not.
MP is better, but I rage quitted after 30 min cause I suck.