Not sure if this is the right place (PF vs DF)

[Thaliss]

If you use PF you can talk beforehand to your team mates and plan to do several runs. People are shy to start teams in the PF.

In the DF, you can have nice or not so nice people but you too can hide behind the fact that you will probably not ever see them again.

[Kloe]

duty finder is good for when you need to just jump right into a dungeon and do it. Party finder is good if you need to specify anything for your party before doing a dungeon. For example you are new to a dungeon, so if you make a party in party finder, you could put in the comments that it's a learning run or something like that. This will increase your chances of getting new people but also people who don't mind helping people new to the dungeon.