The best quality about this harness is its gender neutrality and easy application. Most harnesses tend to be overly "feminine", which can be problematic for gender-bending style. This boxer brief offers a more gender neutral aesthetic, while also maintaining stability. Unlike men's briefs, this harness fits close to the skin and doesn't have that unwanted "bulge" area.

In terms of sizing, I would strongly suggest properly measuring you hips for a snug fit. If you shoot for a larger size, you might compromise dildo stability. I found the sizing system to conform perfectly to my actual hip size. I would also suggest trying on this product before washing. If it fits well during use, don't dry the harness on a high setting. I like the fit, so I wash the harness and subsequently air dry it or throw it in the dryer on the "delicates" setting.

The o-ring seems to be rubbery, which allows for some give. I usually buy dildos that fit the o-ring capacity, but I have a dildo with large ridges and the harness ring is pliable enough to fit the ridges.
Probably the best facet of this harness is its ease of use. Instead of tedious double-straps with oversized ends or the discomfort of g-string harnesses, this boxer harness allows for 1) easy and quick wear and 2) the ability to wear the boxer briefs as underwear. If you think you might get lucky, you can wear these briefs ahead of time and quickly slip in a dildo when it's go time. Also if you're a trans boy or gender queer, the boxer brief allows for packing anytime.

Finally, while color often isn't much of an essential, it seems important to note that the "red" boxer actually appears burgundy (which I actually like more). It also comes in a discreet pouch for easy storage.