I am more familiar with ACR than DxO, so I may have been a little biased when I did my evaluation of DxO. But ACR also isn't my preferred raw converter, so I don't think it could've been a very strong bias. I'm really partial to Raw Shooter Premium, both for it's workflow and the results I get from it. So while it could easily be a case of "sticking with the familiar", I think "bias" is probably too strong a word to describe it.
It's been a few months since I last tried DxO for full raw conversion, but I recall finding that DxO produces too much contrast for my taste. Just saying "too much contrast for my taste" doesn't really adequately describe it. There is also sharpening going on, but also some smoothing for noise reduction. I just didn't like the look of the images as well as what I was accustomed to, and found it easier to get a look I like by letting DxO do what they're good at and then finishing up with ACR. It may be possible to tweak DxO's settings to get what I wanted, but this method works for me and I didn't pursue it further. If Raw Shooter Premium would read a DNG produced by DxO I'd be even happier, but it won't.
So my investment in DxO is strictly for their lens correction algorithms, and just for that it's worth it to me. To me it's an extra step at the beginning of the process for situations where I feel lens correction is needed, but then leave the rest of my workflow intact.
I don't feel it's a time issue, as I don't mind the extra time DxO takes to process images. I also tend to do as much optimization as possible in the raw converter, preferring that to leaving extra work for Photoshop. It's really just a nebulous "I didn't like the look as well as what I'm used to." Sorry I can't seem to describe it more precisely.