I am using a scuf 4ps. My experience is rather mixed.
I ordered mine with a grip on the back. The problem was that they didn't integrated the grip perfectly. This resulted in some edges that were extremely annoying during gameplay. So I send it back and they fixed it (I had to pay for shipment of course). Now I use it always when playing shooters and it seems to work just fine now.
However my friend had an even worse experience.
He had input lag and several other issues that he could not fix. After sending it to repair it seems fixed now but these problems seem to occur very often with scuf controllers.
If you want one for xbox rather get an elite controller These probably have way less issues, since they are official products.