I did post here a while back on the (New) Atari VCS - but this is more focused on the "Modern" controller.
First off, this is my favorite controller I own. It's SO comfortable, the buttons feel amazing, and it looks awesome. It's basically a better designed 360 controller. Very smartly designed D-Pad. Triggers are thicc and smooth.
The biggest downsides are, the bluetooth is super flakey. Not a huge deal as it comes with a really nice robust and long (5 ft?) USB cable. The bluetooth works perfectly in Atari OS but basically nowhere else. I have had it work on PC briefly, but it disconnects a lot. That could be linux/my bluetooth dongle.
You also cannot actually use it on an xbox, wireless OR wired, even though it has "xbox mode". It's a bit misleading they call it that when it really only works for PC.
Anyway, if you like interesting/different hardware, thought I'd bring it up! Maybe someone has an Xbox One controller they can compare to it? I do not.