I'm pretty sure that Bernina model was one of the top picks by Consumer Reports -- March 2008 or 2009, I think.
I love my Bernina, but haven't used a Viking so can't compare.
Here is a link to a thread on the PatternReview website. That website is a good place to research opinions on different models of machines. Haven't read this entire thread, but hope it is pertinent to your question.
http://sewing.patternreview.com/Sewi.../topic/37620/1