Do you mean the jock strap style vs g-string style harness? I don't understand the question.

The harness we have has a back that is easily removable...seems like that is the best of both worlds since it allows for the use of pretty much any harness compatible toy.

The question is dealing with harnesses that have a "pad" of leather or other material that fits between the dildo's base and the wearer. The advantage of this is that it minimizes the risk of pubic hair being caught and pulled and can also make a dildo with a "hard, pokey" base more comfortable.

The disadvantage is that you can't use a double dildo in one unless you remove the pad, and that it can be harder to clean in some cases.

We have both, but tend to use the "backless" more.

I have both, and I prefer the backed one for several reasons. First and foremost, a leather back absorbs some of the force of the thrust, meaning less soreness during extended sessions and after. I happen to prefer the feel of leather against my skin rather than silicone which can have more cling to it. Also it minimizes the sweat and fluid from coming in contact with the back of the toy (especially relevant when using porous elastomer cocks like Silky, it's good to minimize direct fluid contact in general). I don't use double-ended cocks at this point so that's a non-issue.