There are no good AR headsets right now. The Hololens doesn't have enough field of view, processing power, or battery to make it very useful, especially not as a development computer of any kind. And while the Meta 2 is tethered to a PC, it's also garbage. I'm not aware of any others that its actually possible to acquire right now.
That's what I'm saying. The Hololens works (for some value of "works", as far as the simple demos go) but doesn't tether. The meta 2 tethers but doesn't work.