FWIW, my experience with a hypalon rib was that it started coming apart at the seams. I replaced it when a PVC rib with thermowelded seams (not possible with hypalon) and was much happier with that boat.
Depending on where and how you use it, there are ways to mitigate the UV effects on PVC. If you get a boat with slip on tubes, replacing the PVC tubes when necessary is a simple task.
Seems to be a bit of truth to the welded PVC holds together better, but the Hypalon lasts SO much longer it's totally a no brainer. And if the seams come a bit loose, very easy to fix with the Hapalon glue.
Personally, I wish there were a good light weight NON inflatable choice.... but just really isn't any.