"303 is an ok product. I have used better."
Like what??? If you have something that's better, tell us what it is - I'd be interested in knowing.
Like I say, in MY case, I've used 303 on my spa cover and my weight lifting equipment, which is black vinyl, sits outside 24/365 and endures 100+ degree summer days...and it looks new.
I'd challenge ANY other product to match THAT but as I say...if you have something you like, tell me. I'll get a sample and test it.