Played a bit this morning before work. MP was laggy even though my ping was 50ish, but that was to be expected on launch day.
Played the first level of SP and it was pretty awesome.
I was frustrated with BF3 single player, but I've enjoyed BF4 single player so far.
Ran into a glitch where I ran ahead of my squad mates and had to back out so they can catch up to me, and the audio cut out, but overall it wasn't game breaking and it was very brief anyways, so no big deal.
Also ran that optmizer thingy in the latest Nvidia driver as well as the video recorder and the game runs as smooth as butter on my system with Ultra settings enabled almost everywhere.