I own a pair and like them a lot.
There is as much difference between the 10x40 bino's
to 15x56 bino's, as you will notice as you have between
15's and the 20x80's ( Doctors )
They are heavy, need a sturdy fluid head with tripod, but for looking over a mile away, and judging what you see, they are great!!!
You can focus each eye seperately. You have 2 spotting scopes
which gives you more light. You will love them.
I hear some people are joining 2 Swaroviski 20x80 HD spotting scopes, but price them! now the Doctors look even better.
I would venture a guess that those that bad mouth these bino's
have never used them, in the right setting.
Steve Cheuvront