I use McGuires marine products and have been very satisfied. In the summer, Fleet Farm carries some of the products, but for a full line, I’ve needed to go online.
There is no single “best” product. With fiberglass maintainance you have to take some time to learn and understand what you’re actually doing and then buy the correct product for the job AND apply/use it correctly.
One thing I will tell you is that for fiberglass boats, the best thing I ever did is buy a variable speed 10 inch buffer. This not only saves a tremendous amout of work, but the results are vastly superior. However!!! You need to use it properly so you don’t damage the finish.
The key is to use the minimal abrasive that will accomplish what you need to accomplish. Then you need to protect the finish and keep it clean.
Grouse