Hughie, I only flew with default gains.
If I'm to blame for what happen I have absolutely no problem facing what it may have been, and wearing it. I did things and took precautions that I felt were over & above what was necessary. Example, after completing the 12 motor to ESC soldering points had enough time to cool, I lifted on each wire to see if it would either break off, pull out of the solder, or if the solder would break free of the board. I lifted to the point that the quad would just begin to slightly raise from the table.
Justin00, the ESC's show V2.0 on the stamp in gold lettering. I was under the understanding that with the combo of V2.0 Esc's and Firmware 4.6 you were good to go. When searching for where to find firmware 4.6 would be listed at, I learned that if you had the v3.08 firmware it contained the 4.6 firmware for the ESC's.
So while looking over the mess after removing the top cover, I looked for anything that appeared burnt, black, or melted, and nothing stood out anywhere. Someone mentioned a mosfet looking suspect. The discoloring that appears on the mosfet is I use flex resin and that is what it looks like. It comes right off like grease. There was several mosfets(board connectors) pulled off the ESC & main board. The main board is broken and the modfets closest to the break were the ones that had pulled from the board. The gps puck is shattered. Several bosses were broken and I had to use a screw driver to line up the holes in order to remove the screws. 3 of the motors turn hard with one unable to do a full rotation. Dirty Bird is right, the impact is what messed them up to the condition they're in.
The condition of the quad after the crash is one thing. But as some have wisely pointed out, there are so many others experiencing the exact same thing. They all have the same characteristics from start up to crashing. It because of that fact, you just about have to eliminate the possibility that the pilot is at fault.