i have a viking designer one and i do love my machine; that being said, really wish i had spent a little more time trying out different machines before purchasing it...it was a major investment (cost more than my long-arm machine) if i had it to do over again i think i would be leaning more toward a Bernina...my mom has an industrial one that is something like 30 years old and still a wonderful machine! the stitches are beautiful. i have a friend who had a pfaff, after 20 years she decided to upgrade and buy a new one, and replaced it with a new pfaff, she is very happy because of the dual feed.
i think the bernina's cost a couple grand less than the vikings/pfaffs...is there a reason you are not considering a new bernina? of course customer service should also figure into the equation.