Gatorback is a bedliner, it is very thick and replaces the surface of the cladding with a tough abrasive resistant coating. Your cladding surface texture will not be the same after Gatorback.
SRN is simply a thin layer of dye. It does not affect the texture of the original cladding. It just dyes it back to it normal darker color. It does not alter the plastic properties of the original cladding but since surface scratches often manifest themselves as lighter in color, SRN does a great job at hiding them.
Gatorback will entirely coat cladding with a full new surface, new texture with different properties of the original cladding. It does not look like original cladding, or act like it. And yes if your Gatorback coat does eventually get scratched or damaged, you can simply spray another coat to "fix" it. (at a much greater cost than SRN)
Hardcore trail riders might benefit from Gatorback or similar bedliner products, but I prefer SRN because it adds no thickness, retains the look, texture and feel of the original cladding, and does a good job of re-mediating superficial scratches from trail brush. Furthermore, when Gatorback does chip off (which it can) you are dealing with a much deeper surface to repair and may require multiple coats of gatorback to get it back into repair. With the SRN dye there is nothing to chip, to fix, you simply wipe on. Its simply a surface dye, not a re-coating with a different plastic like Gatorback is.