I love the thread cutter when paper piecing, but otherwise I don't use it. My Babylock Serenade leaves thread tails between a quarter and a half inch long. They are just long enough to make a little snarl when you start stitching again. It's on the back, not visible, but it still bugs me, I just don't like that little snarl. And occasionally the top thread immediately unthreads itself past the needle when I start stitching again after using the thread cutter, and I have to rethread the top thread, pull it out to a long length and hold it anyway when I start stitching.
And that really bugs me. In the end, the thread cutter doesn't thrill me the way I thought it would. Only use it for paper piecing--then it's great.