I have paired Superior's Bottom Line in the bobbin with So Fine! in my top thread without any issues. I will admit to doing this only twice, so my quilts haven't gotten a lifetime of wear, however, my Bernina absolutely loved the thread. And I loved having less lint. The only snag I came up against is the thread is a bit more slippery, so I tended to backstitch my seams. But, all things considered, I'd use Poly again for piecing in a heartbeat.