When I was in Europe,I had Wilbers shocks in my CBR, my 1150 RT and my daughter has still got them in her Hornet. Qualitywise Wilbers is at least on a par with Oehlins, only much cheaper. Due to his long racing experience, Benny Wilbers, the factory owner, is the no. 1 expert on suspensions in Germany. He has written a standard textbook on suspensions, which I found very useful to read and which has tremendously improved my understanding of the matter. You will find it on the homepage, but I do not know if there is an English version.
What I found extremely helpful (and an advantage over Oehlins) is that they manufacture the shocks according to your personal requirements. When you order, they ask you to fill in a form sheet and to state your weight, riding style etc., so the shocks come customized to your needs (valve settings, spring rate etc.). The quality is superior, beyond any doubt. I would have fitted them again to my GS, but unfortunately I didn't find a dealer in the US.
When it comes to road performance, there is no difference with Oehlins at all. Fit them and you wont't recognize your bike anymore.