Hello and welcome aboard from Germany.
Although Gütermann is a german brand, I have to confess, I didn't give the quilting thread a try yet, but LOVE it for piecing. I prefer cotton thread, because thats the way I learned it, cotton fabric with cotton thread.
Robison Anton I liked a lot, King Tut has so wonderful variegated threads, but my machine doesn't like it. Aurifil is my fav. brand so far.
Enjoy your quilting adventure and please make sure to show us some pics of your work.