Didn't seem as if the overall brightness of the screen was as good as my old (and dead) 2011. And I believe it is slowly getting dimmer, although this is tough to confirm. I also have a ReallyReallyOld one that has dimmed to Warmgrey#3, but that is understandable. Anyone else? Also, this model is just slower in response to anything. A screen grab; opening anything; it's just way slower than older iMacs or any of my laptops. Apple said "oh that is normal" and I got mad enough to just give up then and there...