I've loved DxO for a while because it handles distortion correctly. Sadly the move to "5.0":http://luminous-landscape.com/forum/index.php?showtopic=26493 has gone poorly with lots of crashes and even with 5.2, people are still complaining about poor conversion and so forth. It's not the only example of software taking giant steps backwards. Kind of sad. I have noticed that Canon's own software does distortion correction and vignette correction, but in the meantime I'll stick with DxO 4.5. But this version doesn't have the latest cameras, so at some point, I'll probably pray DxO gets better or go back to the manufacturer's utilities for this all important camera-specific and lense-specific correction of optical distortion and vignetting.
When DxO 5 isn't "crashing":http://blog.richnetapps.com/index.php/raw_lightroom_dxo_capture_one, it fairs quite well against competitors like Adobe Lightroom and Capture One. While DxO's main strength is geometry correction, it does general image correction with everything from smart vibrancy (kind of a intelligent version of turning up saturation). It can overboard with tings like Shadow Recovery which in its default makes pictures too bright (I normally don't use it).
Where DxO's new engine seems to have the most trouble is in color artifacts and isn't very sharp. Lightroom is pretty good at this kind of RAW conversion. And of course, it has terrible stability problems, crashing 80% of the time at least in one review.
The other reason the right tool is important is for something called "demosaicing", this is how the RAW image which is what comes out the imager (well, raw, 🙂 is turned into a usable picture. Apparently, Canon's own DPP is very good at this, but its "sharpening":http://www.fredmiranda.com/forum/topic/595717 is primitive. So there is much debate about the best sharpening tool, is it Photoshop's ACR (Adobe Camera Raw) which is a RAW convertor or is it a third party too like Capture One or more exotic tools like