I haven't really found something that explained Doosans approach very well yet. I do know it is non-dpf.
DPF's need to regen, nothing else does. As jav explained, it simply reduces the soot to just the ash by heating the DPF up. This can happen passively with no added fuel if you are working the machine hard, actively with added fuel as you are working with the machine, or parked with added fuel if you ignore the DPF cleaning for too long.
Obviously its nicer to not have to deal with one at all, but like everything its only one factor to influence a purchase decision. IMO its one thats pretty low on the list too. There are also sometimes tradeoffs on how the OEM gets their engine to meet standards. They may use new tech that has some bugs to work out, or some alternative system with its own downsides. All of the new equipment has a lot of emissions controls, they vary in their approaches and designs but I wouldn't say one excels over the other enough to say buy brand a over brand b just because of their emissions system.
DPF's have been out for quite awhile now and while there were a lot of bugs originally, they have gotten a lot better.
On the D series Cats, they will flash an indicator when the DPF needs a forced regen. When that indicator comes on, turn the hand throttle into the green area and keep working. The machine will also start a regen on its own if it sits idle for a minute or two. It will rev up and start performing a regen until you want to move it again. If you ignore the regen and do not increase the rev's or let it do a parked regen it will go into the next stage after awhile which requires you to park the machine for a regen.
At some point the DPF will be full and need to be replaced or cleaned off the machine. Cat says the DPF should last 3,000-5,000hrs in these machines. I do not know what Cat has for a system right now. With many of these engines they simply have a core system setup where the dealer will replace your filter cartridge with a cleaned one and they will keep yours to clean and put in the next guys machine. This service costs a couple hundred dollars usually. It is an extra expense and inconvenience, but with the long service interval you wont be doing it often.