Another happy Zipp 303S owner here.
From my perspective the hookless aspect is a non-factor. I was planning on only running tubeless tires on these wheels regardless, and I have no need to go over 60psi, so the absence of a rim hook seems to have zero impact on anything I've noticed.

I'm around 165lbs and I've been using GP5000 S TR in 28mm size for road riding @ 60psi. For gravel/CX I've run a few different tires between 33-35mm @ 25-40psi. I did burp the front the other day in a hard grippy corner when running 25psi, so I probably will stay above that number going forward.

Overall the wheels are great - the wider internal dimension works well with a range of tire sizes and they're reasonably light/fast and they look cool with the subtle graphics. Zipp's lifetime warranty seems pretty solid - hopefully I never need to use it, but nice to know that it's there if needed.