Still too early, but noticed that it took several hours before it would connect to 2 different servers here at home with smb shares.... now both fine and working correctly.
After several sleep/wake cycles on this iMac it has not had a disconnect eject error with one of my Lacie thunderbolt drives. Had to use amphetamine to keep the 2big Raid from being dropped before.
Lastly I have not noticed any strange graphical glitches that would happen on occasion often just from switching from mail to different Safari pages.
So, for me, looking much better and aside from that delay in accessing network shares everything seems great.