I never actually owned a Dan Wesson, but I was seriously considering one and comparing it to S&W, so I did an extensive research and collected a bunch of opinions of the owner.
Majority say, that DWs are very good quality, easily on the par with S&W. They have have a supreme accuracy, as good or even better than S&W. But their action, while decent, supposedly is not as smooth as S&W L-frame to which they are compared size-wise. As for models with changeable barrel, the quality or accuracy is not effected. However you need to use the barrel tool properly otherwise you will screw up the gun.
I hope this helps and I am sure actual owners of DW will add to it. All in all DW seem to be great revolvers. I still think I'd like to have a set with changeable barrels one day.