I used the cheap Harbor Freight knee pads the past 2 seasons, and they were fine but got uncomfortable after a while. Recently I picked up a set of the Klein Tools gel knee pads. They have a lot more cushioning, a flatter face, and the rubber outer coating is more rigid, but still soft enough to grip the tree well.
Highly recommend for $25.
You sir, are amazing. I’ve been using a pair of foam cheapies from ace hardware, maybe $20 a pair. They haven’t been bad and were a good start but the foam compresses after a while and they slide up and down. The Velcro straps are annoying but functional, though they do make some noise on one pair of my pants. So I ordered these kleins and hunted them this morning. Night and day in all aspects. This tree was more of a leaner than sitter so I’ll need more time with them but I know what the verdict will be.