I have a HV Epic, a Pfaff Performance 5.0, a Pfaff Creative 2170, and a Pfaff Creative Sensation Pro II.
Prior to the HV Epic, I had the HV Designer Diamond Royale which I traded in. The bobbins for the HV Diamond series, and the Pfaff Performance 5.0 are indeed interchangeable. When I traded in my HV Diamond for the Epic my dealer told me you can continue using the bobbins I had for the HV Diamond on my Pfaff. I do it all the time. Also, the IDT on the Pfaff is great for piecing, as far as "Made in China", a long time repairman told me Bernina was made in China before Pfaff and HV. In fact they all are. Each machine is still designed and engineered in it's original country, and the final assembly is in China.