If you are willing to spend $300 on waders, you should really only be looking at Simms waders. I know several fishermen (including myself) who have given other brands a try, but all (who spend $300+ on waders) eventually default to Simms.
Also, you could be prematurely wearing out your waders by not wearing gravel guards, or maybe your wading boots allow too much sand/gravel to come into the boot from the sides (some have crappy mesh sides) and that can cause a lot of friction between the bottom of your neos and the boot.
Orrrr, it is simply a crappy wader. When i buy some piece of gear, i often ask myself "what does this company know about making <item>?" Just like i wouldn't buy a fishing rod made by Simms, i wouldn't buy a pair of waders made by Redington.
I might buy a higher-end Orvis, Patagonia, Bare or Arc'teryx if they ever went into the business of making waders.