Crunching Numbers

I knew that my 28-300 lens wasn't great when I bought it. I wanted it for flexibility, not performance, but it's good to know that it will at least perform better on the full frame camera for which its purchase was intended, at least according to DxOMark. I've heard some criticism of DxO's lens comparison and I've even disagreed with some of their findings myself (they say that the Tokina 11-16 is best at f/2.8 whereas my own observations and indeed common sense suggest it's better at f/4 rather than wide open) but really, what better system are you going to use when researching lens purchases?