I'm running it on ultra everything and the graphics are great. Cinematic are usual blizzard quality but there are scenes in between missions during the campaign where you advance the plot lines and change your loadouts and that part is really well done as well. Even the in game graphics have surprised me. There are little details in the maps that really make the game shine. Overall I am continually amazed with the level of polish of the game. Even the achievements, profile, friends list, and bnet are all very well done.
I beat like 20/26 missions of the campaign on Hard then put it down to Normal just to get through the story a bit faster because the missions started to take a while (I would have to redo once or twice to get a handle on what I should do). The fact that the campaign is non-linear is also nicely done. There was a mission I had some trouble on until I realized that if I did another mission to unlock a specific unit, then that mission would be significantly easier. Definitely a nice feature.
The multiplayer is very challenging. I was never good at RTS because I had trouble handling so many activities at once. A typical match requires you to micro your base production (scv and buildings) while scouting your enemies, then you need to start building tier 1 units, launch an attack, defense, or harassment mission, then build an expansion, continue production of tier 1 while starting up tier 2, then building a 3rd expansion and from there my mind just explodes. Figuring out all the counters, being diligent to protect teammates and assist on offenses/defenses and protect your own bases from harassment.. all while understanding the counters to every unit.. feel like my brain exploded lol.
That said I'm in 4v4 Platinum league now which is the highest available. I'm going to be practicing a lot more vs. comps and in quick matches before playing any league games though. I felt like a novice on my most recent match..