On my longarm, I use Superior Threads King Tut thread for quilting, both on top and in the bobbin. I love the variety of colors, especially the variegated threads. I will sometimes use Superior Threads The Bottom Line in my bobbin, as that is more cost effective than using the King Tut thread. Just depends on what look I want on the back.
The embroidery machine gets Madeira Rayon No. 40, and the bobbin is the Finishing Touch. I’ve had good luck with both.