Just used the Atlas for about an hour, I like them. I previously had a set of Turtle Beach XP500 that I used a lot on 360 but sold them when I got an Xbox One. Trying to cut down on clutter and cables, so the Atlus were right up my alley! Also wanted one headset for both PC and Xbox One, so this seemed like the right and only choice for me personally.
They sound pretty good, I honestly couldn't tell much of a difference in audio quality between the XP500 and these, aside from the surround sound vs stereo difference. Loud and clear. But lets be honest, no sub $200 gaming headset is going to give you audiophile quality. I just wanted something for late-night gaming when I probably shouldn't use my home theater surround system as loud as I want. And if you're in the same boat as me, these are a great comprimise. Even though it was stereo, they displayed good sound separation. At least in PvZ Garden Warfare.
Haven't had a chance to test them on PC with the included USB cable w/in-line amplifier but I will test that later tonight and post back if anyone is interested. I love that it came with this, otherwise I wouldn't have bought it (or any other XB1 set).
My only gripe, on first use they are really tight fitting! They clamp your head really tight, which compared to the ever so slightly loose fitting XP500s...were a huge and stark difference. I had to hold them open and bend them outwards for a few minutes and break them in and they feel much better now.