I haven't noticed any streaking issues with OCW using it when the paint is wet. I still flip the drying towel over for a final wipedown around the paint just to make sure I got everything. If you flood the paint before drying you'll sheet a lot of water off and this will help prevent any excessive dilution that could occur if the paint is too wet. So give that a shot with OCW if you're short on time.
I really like using Sonax High Speed Wax when the car is wet as a drying aid, this is what they primarily designed this product for and I've noticed great results. For me it seems like it's the perfect consistency and spray pattern to help clean up wet paintwork. I'll have to open Prima Hydro up and test both of those out together.
With regards to UV protection, I feel that if you have a quality clear coat applied to the paint that hasn't been thinned by excessive wetsanding or heavy cutting and you maintain this paint through regular washes, waxes/sealings, then you're not going to notice any significant UV inflicted fading. Many users on this forum will testify that they've been able to maintain their paint using a variety of different products over a very long time period. So I purchase OCW less based on the UV claims and more on the ease of use, nice scent, visible durability, great results and low price. But I'll have to spend some more time to run through Optimum's testing to see what kind of results they got, here's the link to their UV Patent and test results down towards the bottom: (
OCW UV Patent & Test Results)