The problem is, we don't have comparisons with other methods of correction of lens distortion. I find that correction of distortion is quite easy with Photoshop's warp and distort features. Correction of chromatic abberration or color fringing is also effective in ACR.
Is the advantage here in DXO correction of lens distortion, that more of the image is preserved? Or is it just faster because it's automatic? Both would be advantages.
Before I got DxO working, I used the CA controls in LR or ACR, and corrected distortion with PTlens. I still go that route for unsupported cameras and lenses. In my experience, DxO corrections are always at least as good as those alternatives. Some of the other things DxO does (like lens softness) make other substantial improvements that aren't really easy to accomplish with the others anyway. But the DxO automation takes all the hand work out of the process, significantly streamlining my workflow, and that's the real key for me.
For some reason, DPP has stopped applying lens corrrections to my 40D files. I reinstalled it, but it still won't work. So I can't make any comparisons there.