Any electronic machine can have rather strange problems and the electronics are not cheap to fix. I have what was a TOL Pfaff, had a board replaced rather than upgrade to a CV. I don't like drop in bobbins and the 2170 was far closer to the 1471 I had and really liked. It's the devil I'm familiar with, although I can luckily figure out any machine on my own.
The 1471 let you make your own stitches by coordinates, and everyone was putting out coordinates. Could have so many more stitches at no cost other than labor.
Threads are funny. I went by a Bernina dealer and they had an 830 running full blast with METALLIC thread. I watched that machine for about 2 ornaments, and no thread breakage. I bought the OESD thread which worked just as well on the Pfaff. The Pfaff also loves aurafil.
We had an older Ellure. There were some things I liked about the machine and others I didn't. My daughter took it over.
I was using it for buttonholes! I do like BL software. I bought Cardworks and the box since it would deal with her Ellure and my Pfaff.
Any machine can go wonky from the getgo - You need a more reliable dealer. If the machine is acting up, use your cell phone and send a video!