After having tried many different programs, I am convinced that DxO is the best RAW converter, especially when lens/camera correction modules are available. I gather that the actual RAW processing has not changed significantly with the latest upgrade. Heretofore, I have relied upon Lightroom for fine tuning and file management of DNGs that are outputted from DxO. I expect that I will continue in that fashion with v6, once it appears for Mac.
I used DxO v5.4 extensively and tested v6 on Mac, when it was finally released. The interface seems better and the program operates more smoothly, but I see little improvement in the quality of the RAW conversions. While waiting for the Mac version, I discovered Capture One 5, which I feel produces much better images, even without lens correction modules. I will not be upgrading to DxO v6. I also prefer C1 to the latest version of LR/ACR. I have not tested Aperture and do not plan to, unless I get really bored.