I'm glad I didn't go with the Nest t-stat, I would've confused the hell outta that poor thing. The Honeywell one is a much better fit for me. Plus I think they're having issues with the latest Nest software as well...
I like the 'acknowledge' feature on their smokes but definitely not worth $100+ per unit to me for that, for the 3 times a year I might set it off by accident. I'll stick with my properly ventilated range and functional kitchen, thanks.
My smokes are all interconnected but it was done when the whole house was rewired, so they're physically wired to each other and a breaker in the basement. Not the easiest thing to try and do on an existing installation but I'd take that over wireless any day.