My Bernina rarely cares what thread I use. If I use Sulky Sliver, I have to loosen the upper thread tension. Otherwise I can use anything without adjustment. My Juki on the other hand can the fussy about some threads. I have found that I have to do some tension adjustments with it to get it to stitch correctly with some thread.
Just for your information, I was having problems doing FMQ on my Juki with Aurafil which I'd never had problems with. The machine had just been serviced and I was stumped. I'd done all the usual, changed needle, re-threaded, wound a new bobbin and nothing seemed to help. I was talking to my friend at quilt guild and telling her how frustrated I was. She told me that she had had that same problem with her machine and finally discovered that it was the spool of thread! It sounded unlikely to me, but I had tried everything else so I got a new spool of thread. I wound a new bobbin, threaded it up and it sewed just fine! No more breaking thread or any problems. I never would have thought that the spool of thread could be defective.