I've used he simms for some time and find them fine. Good foot protection on coral. Have a new pair of the marlwalkers I am going to try out this Winter. The key is to wear neoprene socks and try to seal off the top so sand/muck does not enter into your boot, or at least into your neoprene socks so it can rub on your skin and cause abrasions. I use a pair of surfing neoprene booties--got them at a store in San Diego--I believe they are called h20. They have a velcro strap at the top to seal off at your shins. Work pretty well, and they are not too thick so size of the boot does not become an issue.
Cattaraugus Creek Outfitters
God does not deduct from man's alloted time the hours spent fishing.