Favorite feature: SPACE! An 8x8 costs little more than a 4x8 (do the math) and IMO is as small as I would go. I have 17 chickens at present, have had more, and my coop is 11x17. Most of the materials were already here so it was a lot less expensive than it sounds -- but in no way is it too big. There is room for two garbage cans to store feed, and a separate 5x6 fenced off area (I've used it for storage, broody, sick chicken, chicks.) And I keep a lawn chair in my coop.
A close second is power. Running power to a coop is not as expensive as you'd think, much superior to extension cords, and makes life so much simpler if it gets cold enough that their water will freeze where you are. Also comes in handy if you need to handle the birds at night (worming, etc.) or brood some chicks (which I won't do in the house.)
A close second is power. Running power to a coop is not as expensive as you'd think, much superior to extension cords, and makes life so much simpler if it gets cold enough that their water will freeze where you are. Also comes in handy if you need to handle the birds at night (worming, etc.) or brood some chicks (which I won't do in the house.)