I have the 4.0 and have issues with it all the time. The manual is pretty much useless. The auto thread cutter gets stuck all the time (the repairman/shop owner) and was told me to get use to it. The needle threader had to be replaced. Had to have the bobbin winder tension adjusted. Was sold a plastic 1/4" foot that broke and when I went back was sold a metal one (didn't tell me I could buy a metal one the first time) so I've learned to ask if accessories are available in metal. I'm now having issues with it stalling when I stitch slow. Don't know if its me or the machine. Just make sure you have a good rep/repairman, mine leaves a lot to be desired.