I am a Campaign Cartographer 3 user and I have the Dungeon Designer 3 and City Designer 3 addons. I can't really see any cons, only that you need Campaign Cartographer 3 to run Dungeon Designer 3. It's great software I think and I am very happy with my purchase.

If you want to see what DD3 can do, you should watch the video tutorials that are available on the Profantasy website.

And as Gamerprinter already said, you can export maps (or parts of the map) picking file types like PNG, JPG and set the resolution.