I can definitely agree on the optics part playing a huge role - but, the HTC Vive Pro actually has a higher screen resolution compared to the Rift S. I don't have them both here to directly compare, so the Rift S may subjectively still offer a better overall image quality, even though the resolution is a bit lower. Maybe you'll also simply get the chance to try both (or any other supported VR headset you're interested in) Lucas Cunningham , to see which one you'd prefer.
True, though very marginal/basicly the same. Also remember the higher fillfactor om rift s because of rgb stribe vs. pentile on vive Pro.. and Rift S is what, 1/3 of the cost of vive pro?
Here is a through-the-lens comparison video