I think the most important point is not the sole of the boot. Unless I am mistaken in my reading, it is the fact that
there is no single reliable non destructive chemical bath or other method that kills ALL invasive species. Some kill the whirling disease parasite, some kill NZ mud snails, some kill zebra mussels, and some kill Dydimo. Chemical baths are inherently unreliable because they degrade and become diluted as they are used. Hot water does kill all of the above, but the most resistant organism to hot water is whirling disease and it requires boiling water. I would not soak my waders in boiling water. Water temps below 200 degrees F do not work.
Everyone says we need decontamination but no one emphasizes the fact that there is not a single method that kills everything that does not also damage equipment. That is a huge problem.
I think we can all agree that felt was replaced with rubber to prevent Dydimo. That being the case, I believe the easiest nondestructive method of killing Dydimo is freezing. If that is the case, and I believe it is so, using overnight freezing for killing Dydimo will decontaminate a pair of boots whether they have rubber or felt soles.
See the recommendation from New Zealand Biosecurity web site on decontaminating felt soled boots and waders:
"Freeze until solid: The time required until the boot is frozen solid will vary depending upon the grade of material, how much moisture it contains and the efficiency of the freezer.
Freezing overnight should work in most instances."
Reference:
http://www.biosecurity.govt.nz/pests...-specific#felt
Another site, Trout Predator had a post from an individual that did his own test of Simms rubber soled boots vs felt. You can read his assessment as well as comments I made about the design of these boots here:
http://www.troutpredator.info/simms-...the-last-word/
I have chosen to use different boots for different watersheds. I also have a one set of waders for Montana and one for Wisconsin.