I've used the NERD 2, heavily for almost a year, for open circuit purposes, mounted via a rail system to a full face mask. I have yet to experience any issue of "white-out" but could see that being a real possibility with the nature of the "heads-up" display, which is otherwise very impressive -- though
@grantctobin is not wrong about that oddball charger, which has already been replaced once, free of charge.
They've got to know something about that issue, since Shearwater has already affixed a secondary strap work-around for it; and what's with that thin, cheap-o security line used on the NERD for tying things off?
For a company that generally has its ducks in a row, it was the one of the few "what the hell?" moments that I've experienced with Shearwater, along with the wonky regulator mounting system that they've developed for OC, which I would never use, except for a bracket needed for the rails (you'd never want to give up your primary regulator, under those circumstances, that's for s**t-sure) -- though I've yet to have any issue with the depth sensor itself, having long put 150 hours behind me (and have also, so far, ducked those Teric battery issues) . . .