I have the Juki TL98E which is an older model than the QE. I use it mainly for machine quilting on a Superquilter frame but lately I've been using it for piecing as well. It's awesome! My favorite thing is the thread cutter...it cuts the thread and leaves exactly enough to start the next seam, so when you finish piecing your quilt there are no long thread ends to trim.
I've also used it for machine quilting off the frame and it does a great job on that too.
I haven't used the Brother but I've heard good things about it.