Pros:
- don't have to give meter readings
- may reduce brownouts
Cons:
- problems switching supplier
- have to arrange for the install
- more complicated meter more likely to break
- there'll be a new version and they'll all need replacing much sooner than a dumb meter, has already happened once
- creates a mesh network over the whole country, god knows what that could be abused for
- security + privacy concerns
- the more people have them installed the more it's going to cost, on everyone's bills
- the meter itself uses electricity, plus the daft tablet thing
Unknowns
- possible different tarriffs for those on smart meters and those on dumb meters, can't tell if pro or con