Wow maybe my river was a freak of nature. The very first throw I made with the disc landed in the fairway, on grass, and there was a huge gouge in the rim. (some hidden rock or stick maybe?) I'll be sticking to opto....
I think GL is generally decent as well. However I can relate to your problem.
Threw a money shot down a fairway, flat,fat, and sweet. Around the 200' I hit one of the small trees in the fairway (which at Summit Park is basically inevitable). Picked up my River, and it took a small gouge out of the rim and the top of the disc. Nothing huge, but definitely did noticeable damage. I was kinda stunned. I still use the disc, and don't have any problems throwing it other than the archer. Nothing else has happened to it since and has hit plenty. I don't know if it was a run, or just a "soft spot". I have seen another River with the same issue and well. My Visions and my other Rivers are fine and get more work.
Its definitely does not compare to DX in quality. It's far superior. However, I had never done that much damage to a Star or ESP disc in a single throw. Thought, truely any Star or ESP disc I have ever throw for the same length of time, has/had alot more knicks and scuffs. You should see my two month old ESP Cyclone.
Gold Line is good plastic, but so are the Target shopping bags. They cannot handle everything either.