I love leather, but it's so expensive, so sadly I've never owned or used a leather harness. However, I found nylon and fake leather to be perfectly functional and comfortable, so long as you find the style and sizing of the harness comfortable.

I found that I preferred the two strap-style harness (with the straps that go around under your buttcheeks) over the thong-style. The thong harness I used just never felt especially stable or comfortable to me...but it was also a really cheap-o harness, so it's possible a higher-quality thong-style harness wouldn't have the same issues. I found the two strap-style to be very stable and comfortable, though (and the one I had was also very adjustable, which was nice). I also liked how cute it made my butt look, haha.

I've never tried one of the panty/brief-style harnesses, but they look super comfy and easy to use. If/when I ever end up with another partner who's into me fucking them, I'd be really interested to try one of those out.

I’m going strapless because it lets the giver feel something and they also can be more sensitive to the thrusts because they feel it. The skin to skin contact is also much nicer. However most people have to use some sort of harness with the strapless ones because things get slippery down there. If you take off the leather front part that most harnesses have and just use the ring you gain the ability to keep the dildo in and retain the skin to skin contact.

We have and use several leather harnesses and find them quite useful. One of the strong selling points is that the hole that is behind the useless steel ring can be stretched to accommodate larger dildos without breaking - we go up to 2.5" diameter.

As Curious Fun noted the two-strap design is more comfortable and stable than the thong design.

Our first attempt at pegging was with the strapless Share dildo - but my wife had a hard time holding it in while trying to thrust. It's short length made it difficult to keep the dildo in me - it just kept popping out. After that failure...

We tried a couple panty harness styles - because full on leather was too much for my reluctant wife to contemplate. But difficulties with instability and handling larger dildos finally convinced her to try the leather - we haven't looked back.