If you don't mind having a facebook account and living by their "community rules", the Oculus Quest 2 is the best value right now. It is not quite as good as the Reverb G2, but you can't beat it for the price and it is outstanding in its stand alone mode.
But if you are like me and primarily want a PC VR headset for the best possible flight simulation experience, it is hard to beat the G2. Every headset has their pros and cons, but the G2 has the best image quality (at least at the center of the field of view) than most if not all VR headsets (I have no personal experience with Pimax).
But the Quest 2 is just a notch below the G2 in image quality and the Oculus software seems more stable with lower overhead than the Windows Mixed Reality/SteamVR combination that you have to run to use the G2 in flight sims. But even that is a tricky statement because WMR has some great features that Oculus doesn't match.
The Quest 2 has some hidden costs:
1) The cheap headstrap it comes with is uncomfortable. You will want a replacement.
2) You either need to buy a link cable or have a state of the art wireless router and buy the virtual desktop app to use the Quest 2 in a PC environment. For better or worse, the ability to connect wirelessly is a unique and potentially beneficial feature of the Quest 2.
3) The battery dies even when connected to a PC via the link cable, so you may need some sort of battery pack to extend its life. I don't have a battery, but I am sure it connects through the USB port, so it may not work well with a link cable, which would make the wireless router/virtual desktop connection the way to go for PC. Of course the wireless connection may have latency and dropout issues. I haven't tried the wireless option as my router is too old to have the bandwidth to make it work well, but I have a few friends that swear by it.
I am using my G2 as my primary headset, but when my first one failed after just 2 months of use, I used my Rift S and my son's Quest 2 as backups until the G2 was replaced under warranty. The image quality difference between a Rift S (which I had, used, and loved since they were first released) and a Quest 2 is tremendous. It hurts my eyes to go back to the lower resolution of the Rift S. I can't even imagine going back to my Rift CV1. But the jump in quality from the Quest 2 to the G2 is almost as big an improvement.
If you have the money, I would get a G2 for PC flight simulation and a Quest 2 for stand alone: the Quest 2 is that much fun! With all the extras you need to use a Quest 2 for PC flight simming, it is only marginally cheaper than the G2, so I would just get the G2 if you can afford it.