I haven't looked at the 4.2, but I have had the Pfaff Expression 2.0 for a few years now and I absolutely love it. I just finished quilting (SID) an oversized king quilt on it. I sew an average 6-8 hours a day on this machine and it has been a real dream. That said, I'm not sure it would solve your neck and shoulder problems. Your machine may be too high or too low for you; you may need to try a different chair. I had back/neck/shoulder problems until I recessed my machine into the table and bought an adjustable office chair. Don't know what your current set up is, but changing position would be a less costly solution. As much as I love my QE2 I would love to have even more throat space for FMQ. I won't let go of my Pfaff, but I'm considering something like a Bailey (in the price range you are looking at) with a 15" throat for quilting only.