Sue,
I have a lot of their thread, and use it a lot. I don't know as much about thread as I do about fabric, so I guess I feel like it's difficult to tell much about its quality, but I haven't had any problems. I use it a lot for applique, especially hand applique. It's just so expensive to have to buy matching threads for applique pieces, that I find the CT thread the cheapest way to go often. I must admit though, that based purely on my fabric experience, I am a bit nervous of their thread, and I tend not to use it on my most treasured projects, or in my Bernina, which is far more expensive than the other two machines I own. If it's going to clog up a machine (and I don't really know if it will), I want it to be a cheap machine!