I was excited to try it because it seems so much more hygienic -- you can wipe it down and the foam won't degrade. But I quickly discovered that it got all clammy and sticky on my skin, and then humidity would build up and fog up the lenses. What! Kind of the same way swim goggles fog up.
Whereas the regular foam padding is... perfectly fine. No sweating, no fog, no humidity, nothing, because enough air seems to pass through and nothing is suffocating your skin.
And I'm not even a sweaty person or anything, not at all. And I'm just reclining watching movies, it's not even for movement. But the silicone layer over the foam just creates this airtight (enough) seal which is just bad all around.
I tried one before the one that just came with the Oculus 2 and thought the same. I guess there is a lot of variation in silicon foam covers, but the standard one that comes with the headset works for me. I sweat a lot when I do VR, so without a cover, the foam head piece is going to get soaked and smelly.
BeatSaber is pretty stationary, so is FitXR. I've never tried a moving around the room/box VR experience (like Thrill of the fight).