Have had them since 2008. Love them, but if you buy feed by the bag and don't have a ton of green grazing for them....it's probably not going to save you any money.
The taste of the eggs, and knowing the chickens are treated humanely, makes up for that for me.
Because I can't kill them, some of mine are older, and I don't want to put lights on all winter, I'm not getting eggs right now. So I bought store eggs....ickkkkkkkk! No flavor, pale yolk....horrible. I actually had to throw a duck egg in there just to eat it.
RE: heat....there are a lot of people in Alaska that don't heat their coop. I have one 3 sided coop/run that is a hard roof and almost 3 fully enclosed sides, but the front is open: they're out of the wind, but never got a closeable inside night coop in it for them: they're fine.
That said...I have a blind chicken that I got in 2008 who I bring in/out every night as I want her in the super insulated big coop: that one is warmer than my living room, thanks to their body heat.