Are we cleaning our plastic fermenters with swords? How are we getting these gouges and scratches? Let's correct the source of the problem instead of blaming plastics. If you are getting scratches and gouges in your plastics due to cleaning, you need to rethink your cleaning regimen.
I used a standard bottle brush on my first Better Bottle. You can see where it was scrubbed, but there are no gouges.
It still functions perfectly well as a fermenter. I take care to be sure it's well cleaned and sanitized, but nothing much beyond what I would do anyway.
I have enough others that I can keep the old one in reserve. Years ago I had two batches that got infected. When I tried to isolate the cause there were enough other batches that went through that fermenter and didn't get infected that I could rule out the fermenter as the problem.
Yeah. I soak mine in Oxiclean for a few days, then hit them with a "red" bottle brush, which is designed for plastics. Occasionally, I'll ball a wash rag up, shove it in the carboy, and shake it all about when I get stubborn debris. Usually a nice long soak does the trick.