I have a Bernina 640 and have to refer to the manual when performing a technique that I don't do very often. I keep it handy. My biggest problem with my Bernina has been the thread cutter. Has anyone else had at problem with the cutter not cutting the bobbin thread but making an unusual noise and leaving a long thread tail? Then I have to remove bobbin and case, rewind thread, and start again. It has been in the shop multiple times, even when still under warranty, and they can't seem to find the problem. The cutter problem even happened once when using the embroidery module so it isn't just me doing something to it.
Otherwise, I like the machine. It just frustrates me no end when it won't cut the bobbin thread and I have to crawl under a big quilt to cut the thread.