The problem is no-one knows which is the best scope. Without trying every scope on the market for a minimum period of 6 months, which will take forever, there is no answer to this question, and then it is dependant on the testers opinion.
I've looked through loads of different scopes, and some that people rave about optically, I've never found that good, the Nightforce NXS's that I've looked through have never seemed any better than an MTC Viper, but Weaver optics seem very good to me, there is only ever a like or dislike based on personal preference.
Oh, and as far as I know there is no measurement for depth of field as there seems no way of actually testing it as its affected by your eye as well as the scope.
I'm currently using a Bushnell 6500 fyi, but I wouldn't take that as a recommendation, as it only works for me when I'm not being a muppet.