Welcome to the Birdforum.
You are in a large market area, so try them for yourself. I would not trust
anyone else in that decision. Your eyes are what is important.
Jerry
I managed to try them both the same day but not side by side.
I guess I had high expectations for the Monarch 7. I've never been a fan of the MkII/III and it's true the FOV, high CA and glare issues have all improved significantly and I found it much more rewarding to use as a consequence. However the outer field softness I found distracting and surprising at that price. It's something you need to figure out for yourself how it works for you. I much preferred the Viper HD.
David
The Vortex cost 700 bucks, over twice the price of The monarchs, they have a lousy field of view, they weigh a holy ton, and I prefer them over the monarchs by a landslide. The images are amazing.
Mike,
If you found my 50% comment shocking have a look at the reviews from Eitans link. He might have preferred the Monarch but have a look at the individual reviews. The reviewer judged only 43% of the view of the Monarch7 sharp or about 27.5* AFOV. The Viper HD on the other hand he found 87% of the view sharp which would be about 46*AFOV (on the 8x). That's a 67% greater radius or about 3 fold greater area in sharp focus on the Viper HD. I know which I'd prefer.
David
I wonder if Nikon, and other full-range manufacturers, may be finding themselves in the curious position of having to "handicap" their lower cost binoculars to avoid competing with their higher priced models.
Whatever Nikon did with the new Monarch (and I'll reserve judgment until I see it. I got a feeling it's a little better than the extant reviews suggest)--whatever Nikon did I suspect was done intentionally. At this point in time, with Nikon's wherewithal, Chinese factories, and a nice $500 price tag, there's no reason they couldn't have delivered something essentially alpha--not flat field maybe, but otherwise alpha. I suspect they chose not to, in order to keep the high-priced stuff in the running.
I could be wrong, but I begin to suspect...
Mark