Honestly, I would buy the Viking if that is the machine that feels right to you. It's a lot like buying a car in that at a certain point it comes down to personal preference. I'm pretty sure all the major brands of sewing machine you mentioned are in a similar category of reliability.
Sometimes even a good brand will have a model that's a dud, so I would recommend reading reviews of the specific models before making a decision.
http://www.patternreview.com is a great place for that. Sign up to be able to look at all the reviews (signing up is free).