You have a lot of good advice for helping stabilize your machine on a tabletop but I think you should still celebrate the new room with a new machine.
Keep the older one to take to workshops and use the advice given here to keep it from dancing. I am a Pfaff fanatic but if I have to buy a new machine I think I would look seriously at the Janome. I do have an older Janome that is great and have friends with newer models. They have not had any problems with their machines and I have "borrowed" theirs when I am at their house and agree they are fine machines.