Hi Ben,
I have had my Janome 6600P for 7 1/2 years now and I love it. I got one of the first ones released, which is not always a good idea, but it worked out fine for me. Most of my minor issues were related to my "operator error". Rethreading and /or reinserting the bobbin thread corrected things immediately. (I still refer to my manual regularly.) I have been known to use all kinds of threads and generally they all work well. I need to clean my bobbin case more often with some of them. My theory is to try it.
It is a solid machine and if your wife can hang in there, I bet she will love hers too. Good luck