I have Vipers and briefly did look at Razors versus them.
My experience before was with $100-150 Bushnells, so the Vipers beat them hands down. I had never experienced the light gathering ability of a good set of optics before so the first time I used them at dusk or in the city, I was amazed.
IIRC, there was a slight noticeable difference with the Razors which I was comparing outside a shop in the bright daytime looking at street signs, but at the time I couldn't justify the extra money for what I took as a small increase in performance, and the 8.5x50 Vipers I was looking at were on sale as they were being discontinued.
The 2x adapters they sometimes offer with the binos, however, are pieces of s**t, a waste of money, and mainly a novelty offering. It quickly teaches you that with good optics, you can actually see object detail much better with a crisp 8 power than a fuzzy 16 power via one of those adapters.