I bought aHorizon 7700 in September. Her name is Maxie. I am still making friend with her. But I can tell you she does not like to FMQ with Superior Threads. I have both master piece & king tut(Iam a thread of the month geek). during the holidays I became best friends with my seam ripper because Maxie did not like the kingtut. she like the masterpiece for piecing.
I bought some Isacord. Man what a difference. No problems at all so I am sticking with Isacord for FMQ.
I do not want to ever be so upset like I was this past hoilday season over a sewing machine.
My suggestion is try a different thread. Good luck!