I'm not sure what the big difference is in these for all practical purposes. I have heard a lot of people on these forums carrying an 80mm spotting scope but others carry only a 60 or 65mm. What are the advantages of a bigger objective? The major con that I see behind the larger scope is bulk. Weight isn't much more than a 60mm but there is a noticeable difference in bulk and when backpacking that is definitely something to consider. What do y'all say?