I am the proud owner of a pfaff tiptronic and a bernina QE.
I find that I prefer the pfaff for piecing quilt tops. You can not beat the dual feed feature on the pfaff. When I use any other machine I find my blocks never got together as nicely as they do on the pfaff!
I love the bernina for quilting! You can't beat that stitch regulator when your doing free motion quilting. It is amazing!
Both machines will do you proud which ever one you decide upon. Try them both before you buy, if you can.