I have been using either 303 or the Boat Bling products. Really happy with both. The Vinyl sauce (Boat Bling) is great, follow up with a quick mist after using the cheapo TnA cleaner from the dollar store to actually clean it.
If you use a heavy rag, put the rag in a plastic bag after protectant (not cleaning) and you can re-use it without much application of new product each time.
The Hot Sauce is money for the exterior too - looks like you waxed your boat each time.