My opinion based on listening to Vipers some time ago is they were good in most aspects, very good in a few, but lacking in others. The resolution/detail level overall was good, soundstaging was very good, bass tone and definition was very good, top octave air and extension was lacking. They are I think a nice speaker, just that they don't really separate themselves from the pack.
But weren't they like $10K new? Again, my opinion that's overpriced ... on the used market I'd say they're a $3000 speaker tops. Now take that same speaker and have somebody who knows what they're doing retrofit with a RAAL on top, then you'd have something