I spoke to our service engineer about the new electric AGA a couple of months ago - we have oil. He said it was a bag of **** - the engineers do not like to get callouts for electric - but an improvement on the old one - basically it is a choice of last resort for those who want an AGA but have to have electric. He said that they can be costly to service a the elements burn out easily or something. I love our oil fired AGA - never had a problem with it and very economical.
My parents had their fifty year old AGA converted from oil to electric a couple of years ago and as a result have stopped using it. It became impossible to regulate and became only good for boiling the kettle. Advice to anyone thinking of doing the same: Don't.