I'm in the very beginning stages of researching these too. For me, warranty length and details of how any issues are handled is a big concern as I will be moving to another state and can't count on being near a dealership for my particular machine. I'm not anywhere close to making a decision yet; still just gathering info and taking test-drives. I plan on really grilling the salespeople at PIQF in October - that's about when I hope to be ready to make a decision.
I really LOVE the stitch regular on the Bernina Q20. I think it's unique among sit-down LA's. But yes, that is one pricey machine!
Does one of the two you've narrowed it down to "fit" you better? Feel more natural when you're sitting at the machine? All other things being equal - which one is most comfortable to use? Is one more quiet than the other?