Glass quality and the coatings are the most important, and usually you get basically what you pay for. Several years ago I bought a Zeiss Diavari and it is about as good as you can get, but if I were buying a new scope today it would probably be a Conquest, 6500 Bushnell Elite or a Gold Monarch Nikon. No doubt with the Zeiss you can see deer and tell what it is that you can't see with a lower quality scope at dark thirty. Something I have seen mentioned several times that I don't agree with is the problem with a 56 mm. I have never had a problem with it, and my grandsons shoot it all the time and they don't have a problem with it.