I have an older Bernina and it sews great with every brand of thread I've tried. I think needle size and correct tension is the key to good stitches. I have no problem using monofilament or metallic thread on any of my machines once I get the tension set for it. I use all brands of thread but I use 60 wt or higher thread in the bobbin. My favorite bobbin thread is 80 wt Genziana or Aurifil thread.
I buy both at Tristan and the Genziana Cotton Mako 50wt/2ply is the same if not better thread then Aurifil.