I have a Fabric Mover. It was the original of the Fab-U-Motion. I think the only difference is the hole is bigger to accommodate the new Diamond. I played with the one at the store and loved it. I finally bought one from a poster on the Quilting Forum.
It will work fine when my machine comes home from repair servicing. I have a D1. The Fabric Mover or Fab-U-Motion will make free motion easier, but don't expect it to be as easy as a mid or long arm quilting machine.
I think you would like the features on the Viking machines.