Thank you for your comprehensive and valuable review. I ordered this item as soon as it was announced on the Nitecore website, because I was excited to discover that a major manufacturer that markets lights at law enforcement decided that normal people were finally ready for 4,000 lumens in this size light.
The user interface is different, but two things that I like a lot are that max mode (turbo) is memorized in the normal mode selection queue, and press and hold for instant turbo from On.
The protected Nitecore USB ported 21700 battery fits in Xtar SC1, SC2, and X2 chargers, but is too long for the VC4, VP4 and VC4S.
Unprotected 21700 cell works great after a spring is soldered to the cell.
Select modes from On by double click and hold.
Flashing voltage reading is much, much easier to accomplish than in the TM9K.
Again, thank you!