I have a 4800: wonderful for piecing, less so for FMQ because it's impossible to get the tension right - there are always loops on the back. I feel I was let down by my dealer and Janome, because I've been back to both several times over this problem and was always told it must be my lack of skill. Now the dealer admits that this machine isn't great for quilting, and Janome have brought out a separate bobbin case. Hmm. My confidence and pleasure in my quilting were all but destroyed by this saga. I've now tried other machines and my FMQ is fine. All that said, I'm now looking for a new machine to do FMQ, and having started off saying "anything but a Janome" I'm now wondering about a 6600, as of all the machines I've looked at, it seems to have by far the most favourable comments and fewest adverse ones.