Ordering all the binoculars to compare is a smart decision. Nothing against the other brands. I would buy the Nikon, provided it fits your face well while viewing and is comfortable in your hands.
When I am looking at products with about the same capability and around the same price range, I generally buy what I consider the brand with the best reputation. The Monarchs are a very good set of glass for the price. Nikon is established as a top brand name with an excellent reputation. I know I am going to get a quality product with a Monarch, and there is a certain amount of security with buying a very well established reputable brand.
Another brand you may wish to consider that has not been mentioned;
Bushnell Forge is in the price range you are looking at. I have owned some Bushnell products in the past, never being overly impressed. Not a fan of Bushnell. I looked at a pair of Forges about a week ago. They impressed me. Granted I viewed them under perfect lighting conditions. The glass was bright, clear, sharp, with no fringing. They fit my hands and face well, better than the other brands I tried. The downside is they are a little bigger and heavier than the competition, but appear better protected against damage. A more rugged design which is a plus since you are traveling. Wouldn’t hurt to compare them side by side to the glasses you ordered.
Allbinos is a website based in Europe. They don’t sell anything on the site. No links on their site to purchase optics through them that I saw. They only review optics and may be a helpful resource in making your decision. Check out the rankings pages. Between the different rankings pages (8x42 and 10x42 rankings pages) they have full reviews on the Meopro, Kowa, Monarch 7 and Forge.