First you need to make sure that you get a full warranty and the other "perks" that go with a new machine because you mentioned that yours is a "demo" model. And find out if other Bernina dealers will honor that.
I assume that there is a Viking dealer nearby for your "alternative" machine....but how "solid" are they? You might face the same issue down the road with the Viking.
I feel your pain because my trusty long-time Bernina dealer retired and closed his store. Another store in the area took over the franchise but I'm a bit leery of a "new" technician -- although he's been through all the training classes etc.
Difficult decision......good luck.