I exchanged my first one (M3) it was 99.5% perfect but had a few lingering issues possibly my fault as I really tweaked it with and upgrade to Education , Hyper V ... also some registry tweaks (turned on credential guard) ... for some reason he 11/2 firmware would not apply. so used my recovery drive, and somehow it did a n in place upgrade got back to pro applied 11/2 firm .Tried to recreate a new recovery drive it failed. Called MS spent an hour troubleshooting, did the built in reset after a bunch of reboots and device manager stuff... then tried to recreate the recovery drive...could not. So I used the online surface image option and again that drive would not work either. Took it back to the store had them help me re-image it and on reboot I immediately checked to see if I could create a recovery drive..no. Also the camera on reboot would not work... So at that point I exchanged it. I think something happened to the built in recovery and not hardware .
My new one I was very systematic in on-boarding it. No internet...Setup...recovery drive, Update another recovery drive, Restore point, install ESET, Update store, another restore point. Then Office.
So far this surface is 100% perfect runs nice and cool 22-45C and actually has even less bottom light bleed. Very happy with the second one. It all works and runs Windows and Office perfectly!