I have used Nu Finish. I lasts based on beading of water, but otherwise I cannot say it does much for the appearance of the RV or for making it easy to clean. This year I tried Meguiars marine protectant. The first coat did not help. It left a mottled appearance with minimal shine. I put on two more coats then gave up. I stripped of the wax with ammonia clean and rubbed with bar keepers friend. Since I had so many coats of wax, I did this carefully twice. After that it was easy. I just wiped on a few coats of ZEP. The RV glows with a nice shine and seems to repel dirt. It has only been a month or two, but according to the internet it should last at least a year and then only require a touch up coat. The ZEP approach is recommended for older RVs, not new gel coats.