Just replacing Apple's slow standard 1TB SATA HDD with a new 500GB f-a-s-t SSD.
Very well and smooth. Only issue was a minor misalignment of the display when re-assembling. Off just a tiny bit, but enough for the discerning eye at the right angle.
Go slowly...and do NOT apply any heat to remove the display. Read this somewhere else and have really not needed it. These displays are NOT stuck on with the same material as laptop glass. You are actually slicing/cutting thru a very thin layer of soft foam...easy does it. iFixit's iMac opening tool...the mini pizza-cutter...works well. I also used several of the "guitar picks" around the perimeter as i worked to help.