Adafruit M0 Feather bluefruit

I saw that, made me smile, thanks for the name check ;)
The 32u4 version is ace, I've upgraded my guggen hat with it. But having seen the M0 version, want that now. Thinking of a better thermostat for my heating that will talk to my phone. (one random idea). My current one is basic, just temp control via RF. So want one to change target heat based on day and time of day. Would need a display too so the eInk add on should be nice. Design still in my head at the mo, got quite a few other stuff to do first. But will get one as soon as it's on sale.