Re: SIMMS Headwaters Boot Questions
I have the Simms Rivershed boot that has the same sole. I chose the Rivershed as it is as much of a rugged hiker as a wading boot as I need something for much the same purpose as you. The Simms sole is pretty darn good for a non felt sole but I added the carbide studs and it's now excellent, I'd highly recommend the same for yours if you choose the Simms.
The Patagonia boot looks nearly the same as the Rivershed at the same price so with that in mind I would try all three and see what works best for your feet.