I have a Pfaff 7550 and I have tried many different threads. It seems that my machine works better with some threads.
I tried Aurifil but it kept jumping out of the bobbin and I kept having jam ups. I tried Connecting Threads because of the price but I seem to get alot of breakage and a ton of lint. The Gutterman is not bad but I have to say that my favorite that I keep coming back to is Mettler Silk Finish Cotton 50 wt. I don't get much lint, no thread breakage and I really like the look of it.
I think it is the fact that home machines were not intended to be used the way we use it for FMQ--constant high speed for long periods. I clean my bobbin case with every new bobbin and I change the needle about every 5th or 6th bobbin.
I do this no matter what thread I am using. I also oil the bobbin case about every 3rd bobbin when FMQ.