I think you won't hear much here about Viking. In the past, they have primarily been manufactured for a retail chain called Watson's. They are working now to build a dealer network. However, since they really haven't had a lot of dealers out there, unless you are in a city with a Watson's, you probably aren't too familiar with them.
My understanding of Viking is they are a decent spa. They are not a top tier spa. They are more on the mid-level of brands out there.
I've not heard much about their warranty and how they do with covering it. Hopefully, you can find someone that has heard a bit more.
If I were you, I'd start looking at the top tier brands. They all have mid-price spas that should compare to Viking.