so maybe there's a bias built in based on the geology of the area one usually fishes in.
Yes. All this felt vs. rubber stuff. It ain't just different opinions. It's different circumstances. Weight is also a factor (meaning your weight). Like most things, it can't be boiled down to "X is better". The devil is in the details.
On something soft, like mud, your sole doesn't have to deform, as the substrate deforms. So what you want is for your sole to DIG. Studs or no studs ain't gonna make any meaningful difference. Something aggressively treaded, like rubber, though, will vastly outperform something flat, like felt. And harder rubbers are better.
Plain rock, well, isn't going to deform, so your sole has to instead. So this is where felt rules, and among rubbers, the softer, the better. Complete opposite as the above.
What about algae covered rock? Well, lacking studs, the non treaded felt never makes contact with that rock. It's like being on mud. Not good. Treaded rubber will cut the algae and make contact with rock, offering some traction, but again, rubber on rock isn't great. Seems we have a problem...
But this is where studs come in, and things get complicated. Studs, obviously, will cut the algae and hit rock. Whether that's a good thing or a bad thing depends.
Lets be clear that rock type is a MAJOR difference. On soft rocks like shale or limestone, studs dig into the rock a bit. Now you've got a hard anchor in rock. Very good traction. Makes you feel like freakin spiderman. If that rock were vertical you feel you could climb it!
On hard rocks, granite would be the extreme, they don't dig in. Now you are walking on studs, not felt or rubber. And the contact area is tiny. Very, very bad. You could skate down a 3 degree slope, lol. We don't have that much granite in PA, but we do have a lot of sandstone and quartzites, which are hard rocks.
And on a tweener rock, a heavier person will be more likely to have their studs "dig" better. As will a lower surface area, i.e. sharp carbide studs better than big flat "star cleats" and the like. And many may notice that even with carbide studs, don't load too many on there, you just want a few so that the weight per stud is greater.
In summary, if you got someone fishing fast water (algae free) on sandstone bedrock, they're gonna say felt rules, rubber sucks, and studs suck. And they're absolutely right.
But, if you got someone fishing slow water on algae covered limestone, they'll tell you studded rubber is the bee's knees, and studless felt is just crazy bad. And they're absolutely right too.
The worst situation is algae covered hard rock. Studded felt, with well worn studs down to the felt level, is probably your best bet there. But nothing is gonna work well...