Nice report. I had bought DXO 6, tried it for a few weeks and then didn't bother with it since 2009. My main work is with LR and Photoshop, and I found the few real advantages in DXO 6 processing were not worth the extra time and effort given what I considered an awkward interface and too many steps before getting an image from the camera through LR or Bridge, into DXO, then back to LR and Bridge.
I saw a demo of DXO 8 last night, and some of the features (especially shadow recovery and noise reduction) seemed good enough to investigate a trial run, since the upgrade price is currently very reasonable. Your review mentioned most of the concerns that I have, and I am now in the process of downloading the trial version.
I checked the DXO website and could not find whether there was a module for the 5DIII and Tamron 28-300 VC lens, so I'll have to wait until I install the trial version. I'm pretty sure the rest of my camera/lens combos are covered.