I've had one of these for about two years now. I recently helped a friend to modernise his Saturn experience and he opted for the same controller, based on my recommendation.
Holding the controller in your hand, it feels like that old friend, the 2nd Model Saturn Controller. Only now it's fully wireless, perfect when otherwise the cabled controllers don't reach where you need to be. The controller feels solid and well made too.
If you get out an OEM controller and start nitpicking, then sure the triggers don't have that clickiness and the D-Pad doesn't feel identical. But different does not equal bad in my opinion, ultimately when you just use it and stop thinking about it, you won't care. It works great and I can sense no detectable change in my gameplay. For example, I am setting new PBs in Sega Rally without problem, I don't get better results using a Wired OEM pad.
I know some people will be considering Lag, but again neither of us could sense any and we've been using Saturn since the days it was relevant. I'm not saying it doesn't introduce any, just that unless you are super-human, it's nothing detectable.
Battery life is genuinely impressive, 30-40h use is easily achieved before it needs to be charged. I have a v1 model, but the new one was a v2. Not sure what changed between them, but on the older one switching it off, by holding L + R + Start for a few seconds, ensures little charge is lost if you don't use it for a while. This doesn't work on the v2, we couldn't work out if it goes off or how to do it. It's a little annoying that details like this didn't make the manual! Best of all, thanks to the replaceable and standardised battery, this won't end up in the bin when the battery eventually dies. Although buying a genuine high quality replacement will likely be a challenge, bad ones won't make it a year. Note, this experience comes from a BT mouse with the same battery type. I'm two years in, the battery doesn't feel degraded, they obviously come with good quality batteries. It's just here as a warning when replacement time comes.
I really only wanted to use this on my Saturn, but the included USB receiver means it can be used with your PC and bunch of other devices with a USB port. For example, my friend uses his with his MD Mini consoles too, which is a nice bonus. Speaking of which, the display/protective case is a nice touch. I'll be honest, it's lost on folks like me, since I use mine enough that keeping it in a drawer makes more sense.
If you just need a wireless solution to play Saturn, you won't regret buying one of these, it's as close to the real thing as anything but the real thing, whilst freeing you from wires.