I have the Janome 6600, the 3160, and on a "spur of the moment" 5 years ago bought the 15000 and have absolutely no regrets. I used part of my children's inheritance and have never looked back. I kept the 6600 so I can stitch on it and embroider with the 15000 at the same time. The 3160 is my little traveling machine. I love my Janomes and the advantage to having all the same manufacturer is the learning curve is a bit smaller as well as some attachment feet and all the bobbins are interchangeable. Making life simpler.
This website from Janome Canada is wonderful and has all kinds of info about the Janome machines. I subscribe and get emails every few days or so with all things Janome. Always something new to learn.
https://janomelife.wordpress.com/