I use both Klasse and 1Z.
The Klasse twins provide a great look and protection.
Klasse provides real protection. Here is how I know without taking someones elses word.
On my MDX I have two coats of SG. One day after usings Sonus Acrylic Glanz, I saw a spot where I apparently failed to wipe it off, so I wiped the spot again, but when I looked at it, the spot was still there. I again sprayed the spot and buffed it a little harder, but the spot was still there. I have concluded that I missed a spot when applying the first layer of SG, let it dry, then sealed that area with the second layer. So, in essence I can see that I have a clear acrylic cover over the spot that I can't remove until I remove the SG. I found that to be most satisfying.
On my other car I have AIO/SGx4. But the detailing illness got the best of me and I wanted to try GW, so I did and I like that look better. It seemed to give it a deeper look. It may have removed a layer of SG :nixweiss, but I thought I could live with that. The illnes bit me again and I decided to try Wax Polish Soft (WPS) and that gave the car an incredible look. I am very happy with that and know that the car is well protected underneath.
In summary, I will always have an SG protection coat on the car and it will be topped with WPS, whether or not I will use the GW is uncertain.