I'm currently testing the Crystal, getting it heavily discounted in the Black Friday sales, I've been a G2 user for years but really wanted a better sweet spot (looking through a straw!) and with eye tracking. The Crystal seemed the ticket with all the other benefits over the Aero. A big one for me was the report of a higher vertical FOV and so better for dogfighting, which is what I love to do, especailly in a Spitfire!
I found the setup fine, had an aftermarket top head strap from my G2 which I used on the Crystal, as it was just painful on my forehead. This did help. Eyetracking was sorted and works really well (thx Matt). However, currently I'm struggling getting a decent performance while flying over the channel while dogfighting 109s, dropping down to 20 fps, this is with a 4090 and a AMD 5900x. Anyway this could be down to my old version of windows 10 and currently I'm moving over to Win11 as this is meant to be better with multi cores.
However, though these repeated dogfight sessions as I kept adjusting settings through OpenXR/DCS and reducing res to try and get a decent FPS, the fact this is a bloody heavy bit of kit on your noggin and swinging it around trying to find your target's wingman, was just painful after a while for me. Flying jets and locking on targets via the radar and generally a slower pace flying is okay, but for me, loving WW2 fights, I'm sending it back and have ordered the Aero while still it's still on 10% discount. Picked up a secondhand version 1 basestation for 50 quid and waiting for the Aero. I hope the lighter weight, a fan (the Crystal was foging up for me, especailly at the start of a session) and the hope of better fps with a more mature software....fingers crossed!!