It really depends on you. Others love the RIR and comets, I don't. 2 years ago I had the RIR, did nothing but pick on the others, the comets already killed 3 of my birds. They are very active, they do well if you free range, but if they can't they seem to get bored and pick. And believe me my coop and run is big! I did everything big when I started because I knew I would get a bigger flock someday. (this year!
) I also did the cabbage thing, and gave them different things to peck at when they don't free range. But yet others had luck with them. GO FIGURE!
I also have buff Orp and they are the sweetest birds, pretty good around the kids too.
I also have leghorns, now some are nervous and some will jump on me just for that treat, and follow me around. They do like to fly though and not so good around kids.
I think it depends on you. How many you are getting, If they will always be able to free range I don't think it would matter much what you got, if you give them lots of love and treats they will be fine. But if you can't free range I would go for a calm and quiet bird. Buffs orp, Black Australorps, Salmon Faverolles, cochins, I even heard the speckled sussex is good. Just look at different websites and hatcheries and they will tell you what is a calm breed and ones that are active.
Good luck for what ever you decide