Husqvarna Viking and Pfaff are both owned by the same firm (so is Singer). I've compared functionality in like priced machines and if I had to guess, they have the same internals and different pretty packages based on the history of the brand - Pfaff a bit more boxy / angular while Viking a bit more rounded. The embroidery hoops are interchangeable, feet are interchangeable. I only wish the bobbins were interchangeable because the Pfaff are pretty blue and Viking are green or a preponderance of pink.
Recently, I had the Opal 690. It was great, but at the end of the day it was small for quilting anything beyond a toddler size quilt. I went to a Topaz and it was awful, I probably got a dud but it was the first disappointment I had buying a Viking. Then I went to the Brilliance and love it. I've seen the Jade in person and the throat is very small.