Steiner is the best rifle scope that I've ever used and it's also one of the most expensive, but that expense translates into durability and reliability. I never have to worry about the turrets working or whether or not it will hold zero. Many of the rifle scopes talked about in air gun forums are not in this category. Clarity from edge to edge, true color and maximum light transmission are second to none. It’s made to be used in any environment; day or night, hot or cold, wet or dry. Unfortunately, the AO only focuses down to 25 yards so it’s not the choice I would make for a spring or gas ram air gun. If you have the chance to handle one of these scopes, you will literally “see” the difference between it and what you are currently using. 

https://www.youtube.com/watch?v=yzx3DscRvwo
http://www.steiner-optics.com/riflescopes/t-series/t5xi-3-15x50
 
"Deja"or for about the same cash you get a kahles that focus down to 8 yard. Most likely not as durabel but lets face it. none of us are jumping over rocks with our few k rifles. Thats for the army to play with.
Most likely not as durable ? Kahles is the oldest scope manufacturer there is :D Don't think they got that old by manufacturing less durable for top price :)

I've used the Kahles K1050 FT once, really crisp and clear image! Don't know how Kahles compares to Steiner but they'll both be top end, I think it'll come down to personal preference which is the best.