Pros: small, less feed consumption
Cons: can be very loud, noisy and talkative
I received two campine chicks as part of a " layer collection" (or something similar). From the very beginning, these birds were flighty and skittish. They could be handled (and were... DAILY) when small, but as soon as they were transitioned from the brooder to the coop, they wanted nothing to do with people. In comparison to my plymouth rocks, they could be considered quite anti-social!
Then, they approached the point of lay... and our silver campine started screeching at such a high volume as to concern our neighbors on either side of us. They thought it was a baby crying! She would shriek and screech throughout the day--sun up to sundown (and no, she was not a rooster- just a wannabe).
It is perfectly legal for us to keep our hens, but out of consideration for our neighbors, I quickly rehomed our campines. As far as urban backyard flocks are concerned, I consider them to be a poor breed choice. Especially if your goal is to raise hens "in secret" and/or want to stay on friendly terms with your neighbors;-)