Neither is glossy. If I were you, I'd go to the 303 website and order their sample kit for something like $4-5 and try the 303, plus a few other products. Plenty to do some dashes.......or, you can find it, perhaps at a local boat dealer to try.
I have both of these actually, but never tried them side by side. By popular vote, 303 gets rave reviews for protection, but if you used either of them regularly, they're both fine.
Try the 303 sample. If you like it, then you're set. If not, the go w/the DP. It only takes a few days to get, plus you'll have a few extra products to try. In the case of DP, AG puts it on special from time to time, so you might score a package deal if you wait. But, I'd give the 303 a shot first.
See ya.
