Found this on Reddit so sharing it:
"So I have been testing Halk Life Alyx on three headsets. I have more headsets I could test with, but my time is limited due to work. Below are some quick notes on each experience.
Pimax XR:
Overall the best of the three, but not on all aspects. The colors, ah the colors, for all other Pimax users, you have no Idea what you are missing. The XR is simply superior to the 5k+, and 8k and Valve Index in the color reproduction and blacks. For this game the blacks adds a lot to the mood of the game because shadows increases a lot to the immersion. Resolution wise surprisingly looks great, considering that is Pentile.
Having a wide FOV benefits can not be overstated, for a game like Alyx is simply a game changer. You gain peripheral awareness over the Index or any other headset cosntraint to a smaller FOV. Having said that, you still feel you have some form of mask because the Pimax in Large mode does not fully cover the entire FOV, is wide but not all encompassing like the StarVR for example. The edge warping although still there is not so bothersome. Once this aspect is fix it will be more immersive. Pimax do suffers a bit from proper image convergence. It can be mitigated to a degree, with the IPD/vertical offsets but it will never match the convergence level of the Index, Oculus, Samsung Odyssey. This may be to an inherent hardware problem with the lenses and even screen position.There is too much lens warping where the eyes meet when comparing it to other headsets, that said, once you fiddle with the offset and the IPD becomes pretty decent and reduces eyestrain.
Refresh rate is actually not bad. Is plenty smooth on a 9900k, 2080 ti. I can not tell too much of a difference from the Index although, after a longer session, I may have slightly more headache prone after the Pimax XR.
Index:
The Index is by far the most comfortable headset, so welcome to test my Pimax 8kX with the MAS head-strap. The most immediate observation with the Index image is the brightness of the display. It is bright! The Pimax XR suffers in this category even compared to the Samsung Odyssey. Having that brightness adds a level of eye relief when you are on a day light environment. The screen-door is also superior, but or certain scenes it didn’t feel better than the XR which is weird, perhaps this could be because the colors of the XR are better and at times things just look better on the Pimax. Because the Index can not create true blacks it can not reach the level of immersion of the of the XR. The image is sharp and the eye convergence is better, meaning the stereoscopy of the image provides better sense of depth, just like the Oculus, ans Samsung Odyssey, but… not by a lot, just that it is noticeable when you switch back to back. The sound of the headset speakers is amazing, and here the Pimax just plain sucks. The Pimax have the worse head-strap in the history of VR headsets, they were drunk when they designed those head-straps
Samsung Odyssey (OG/ Plus):
I own both versions of the Samsung headsets.The best image in all headsets so far is the Odyssey Plus followed by the OG. Even more so than the Index. The Index while slightly less SDE just can not compare to the vibrancy of the this displays. Surprisingly this displays are not as dim as the Pimax XR! From what I have heard, the Pimax XR uses the same display, but in reality it doesn’t perform as good. The Samsungs display are just better! As good the colors are on the Pimax XR, they lack the color saturation and vibrancy of the the Samsung adding the brightness lacking of the XR you get the best Oleds not being the StarVR. The headset is ok, comfortable, not like the Index mind you, but good enough that you don’t have to fiddle with the straps like the Pimax without he DAS Mod which I am not going to do. The included speakers are pretty good to. But the hindering issue is the FOV. It is the smallest of the bunch and quite noticeable when you switch back to back. For Alyx the scope of the environment is a huge part of the impact of the game and here, there is no way of ignoring it. Even with all of the Pimax XR flaws it is superior for the game. If it was Beat Saber, forget it, this headset is much better than the XR.
Conclusion:
Overall the Pimax XR is the best immersion of the 3 headsets. Wide FOV, Oled display transform the environments truly creepy. The Samsung Odyssey clearly is the winner in the image quality department, is just sharp, bright with amazing colors and black, simply can not be beat. The Index have the smoothest experience when it comes to the refresh rate and that can not be ignored, but didn’t affect me as much as the XR
They all work well on Half Life Alyx and Kudos to Valve for such intriguing and well executed game. If you are a fan of Half Life and like dark games in general and consider a Pimax headset, then the XR maybe a very strong contender."