We've had enough of our gas supplier screwing up our bills with their deliberately wrong estimates, so we're looking for a new one.

We're using it as an excuse to go green and swap both electricity and gas to a green supplier. We don't mind if it costs a little more, we're mostly swapping suppliers due to bad service, not cost.

At the moment the choice seems to be between Origin (who we've previously had but are willing to try again), TRUenergy and Simply Energy.

Anyone have any advice?