Anyone got one and what do you think?

Have an opportunity where one might drop straight in to a relative's
system and improve matters (they have odd but mostly regular occupation
times and hate manually programming timers, which would make a 24/7
programmer a liability for them).

The wiring at the wall thermostat is fortuitous (ie there's a live,
neutral and demand wire) which makes the NEST back end box a straight
drop in. The fancy dial bit can be mounted in a more optimum place in
the living room.