Do you live or work in Zurich? Then we can meet sometime and try it. I also remembered that I used my Sigma Art 18-35 (APSC) for a while. That actually went quite well. But in the meantime I have a Sony 16-35 2.8 GM and that is really worlds better.
A very good mix of price, quality and flexibility would certainly be the 24-105 f4 which came out 3 months ago. Unfortunately it is still not available, I am waiting eagerly.