NO problems here, but I only use if for the durability, don't really care for the look. And I only use it on vehicles that are basically marring-free. Actually, these days I only use it on wheels and the minivan.
When people find it hard to use I hope they just find something they like better and get on with their lives. Any more I pretty much about the idea that somebody oughta struggle with a product, like mastering KSG (or anything else) is some noble goal that'll build character or something. There are plenty of alternatives and this detailing stuff is supposed to be fun.
I have used and have had no problems. BUT I use it on my lighter color cars, as I had streaking on black and side by side NXT wax looked better. So I use it on silver and other lighter colors .
The PC with buffing bonnet works well for thin even application; but I find it faster to lay it down kinda thick (enough to see easily) with a dry MF pad, wait 10 minutes or so, spray lightly with Acrylic Spritz (discontinued), then buff off. In this way, the SG is only "diluted" with a little Spritz during removal. I just hope I can find another QD that is as SG friendly as the Acrylic Spritz. I'm down to my last 4 oz of my beloved Spritz.