I've heard it somewhere on this forum that most people who have DMS also have Dragonfall. That's just what I've heard. I'm not sure myself, but I may have to use Dragonfall resources personally just because it has the type of art assets to do what I want to do.

My impression is that most players who are actively playing UGC already have Dragonfall. I have a mixture of Dragonfall-required and non-Dragonfall mods, and they're all acquiring new subscribers at about the same rate... there are definitely soon people out there who don't have DF yet, but they seem to be a minority. And, of course, as time goes on more and more of those people will probably pick up Dragonfall.

If you'd like to use the stuff in Dragonfall and feel it would make your mod better, go for it! It's also worth noting that, if you add the Dragonfall dependency, your players will be able to use the new player portraits and totems in the character creation process, which people seem to appreciate.