I'm not sure what you are calling "big ones", and I'm sure many will disagree with me, but I really have not been satisfied with the mini binoculars.
Most of the small ones I've tried are way to high powered for the objective size (like 10x25) and are useless until the sun is well up and stop working for me as soon as the sun starts setting. Of course they weren't Walt's Leica glass, but I did try one of the lower end Zeiss. I've had an 8x32 that was compact, but way too heavy. A 4x25 would be a great woods glass for bow hunting, but I don't think anyone makes one. Even a 6x25 would be OK, but again, nobody makes one that I know of.
So, I lug along my 8.5 x 45 Nikon HD and enjoy a bright, clear view and live with the size. With one of the better harnesses it is not bad to carry, or with a slightly longer than normal strap hung over my shoulder and under the arm on the other side.
I will be watching this post for ideas. Or, if I win the lotto, I will look seriously at a nice small set of Leica glass.