Maydup, you ask 'what's not to like'?
Well, for a start it means your supplier has remote control over your supply, and could cut it off at any time. It also means that in the future, tariffs could be brought in that change throughout the day according to demand and you would have no real idea about what you're paying at any given time - unless, of course, you sit there watching it.
Smart meters won't work properly if you have a poor signal in your area.
It could make it much more difficult to switch suppliers, especially if you have had one of the duff first-generation meters fitted.