I used to have the MB4 and hated it. It was loud and heavy and I could never figure out how to get things centered properly. I sold it and haven't looked back...
Having said that... IF my dealer had any kind of support at all - even a new owner class, it would have been helpful but they had nothing, nada, zilch...
I love my Janome sewing machine. My first embroidery machine was the 350e which I adored and only sold to get the MB4 because I wanted the bigger sewing area (oh and the MB4 is a bugger to thread unless they have changed it since I purchased mine) I now own a Brother 4500d and love it.
The woman I sold the MB4 to loved it though. She was starting a home embroidery business and she seemed quite happy with it...
So I guess for some they probably love it. I hated that machine though. Literally - I have an industrial wheely cart that my embroidery machine sits on. I used to have to wheel it out of the craft room and down the hall to use it. It was soooo loud!!