I love my ORVIS Stockingfoot Breathables! I pick the sole I want to use on my ORVIS Convertible wading boots and I'm off!
I don't know about other brands but the ORVIS Stockingfoots have a great "flap" that goes over the boot and keeps sand out. I have not had a problem with sand in my boots as of yet! (knock on wood!)
Good luck,
Rob