The DPF are the noticeable part of the new "clean" diesels, the EGR is the other big culprit.
The cleanest burning diesels and most fuel efficient to me were the pre tier 4 common rail units.
With no EGR and no DPF those engines ran clean started very well and lasted.
A mechanical injected diesel runs good and will noticeably smoke under heavy load, and the oil will get dirty looking fast (soot).
The early common rail unless "tuned for max power" ran excellently, didn't smoke near as much, started better and the oil would stay clean for a ling time.
Then the EGR crap started, power was down, starting was not quite as good and the engines soot up the oil even faster then the older mechanical engines did.
With the EGR they then stuck on the DPF to collect the soot that was increased from the EGR and now we burn extra fuel to heat up an exhaust filter to burn soot.
Plus we have DEF that gets injected in small quanities to reduce NOx supposedly which doesn't work quite often in the winter.
Of course winter operation is when the DPF has the hardest time getting up to temperature and uses even more fuel to try and get it to temperature and clean up.