I have a Nikon 600 and I would say it does a decent job, but not great. The problem I most commonly find is not being able to get a reading, even at distances well below 600 yds. This is very frustrating on a hunt. What I end up doing is targeting an object near the point I want to rangefind and use that as a reference. This will work in most cases. When it does get a good reading, it is very accurate.
Now, what makes the Nikons attractive and still worth considering is their very small size. If the new compact Leica's had been out when I bought my Nikon, I would have picked one of those up instead, and, actually, will probably do just that in the next year or two. The regular Leica's are simply way too bulky for a stalk and hunt IMO.