So far on all three of my machines Ive had the best luck with good ol Coats and Clarks.
Just set up my strait stitch machine for long arm free motion. Tried several threads, Connecting Threads just kept breaking. Got Coats and Clarks machine quilting thread and it works perfect.
I also have a cheap Brother and a Viking Sapphire and they both like Coats and Clarks the best. Not the cheap kind that Walmart carries but the kind with the snap up top.