I've got to start somewhere! My system is a domestic sit down Bernina 820. Part of the reason my friend gave it to me was she felt it was fussy about threads, and my friend although she loves Berninas just didn't click with it. "Bernie" and I are working well together, it does have some thread issues but I think that is more along the lines of the manufacturing issues that made them drop this model than the threads themselves. Still, I have to admit that Bernie does seem to like Aurifil as a top thread.
When I was using the long arm, we found the pre-wound bobbins from Superior gave us better results than winding our own, plus the weight meant more was on the bobbin. That was a Pfaff with Size M and although I come across L and 15 bobbins, I hardly ever see M around town. I think those were probably So Fine, but I'd often get a couple of the individual prewound "sale" bobbins (where they send you whatever color) so I'm not sure.
The next quilting t-shirt I get will be "It's all fun and games until the bobbin runs out".