Re: durability felt vs rubber?
I have worn (fished with) Bean Aqua Stealth boots since the late 90s; I think it was near the time that they first started making them (having them made). The boots and the waders (also LL Bean) are still going strong 10+ years later. I am certain that I do not fish as much with waders as many of you, but the boots and the waders look like they are new.
In terms of grip, the Bean boots are very good, but I would have to say that felt (I have some hippers with felt soles) grips better on rocks with slime.
Taking everything into account, I prefer the Aqua Stealth soles. It works as well as felt in most conditions, and it wears much longer. My rarely used hippers with felt soles show much more wear. Also the rubber sole does not take days to dry, which is important if you are on a trip.