Aga's are great, as long as you've a house that 'works' with one.
New they are a fortune, s/h cheap as chips (the Redfyre we took out went for £1.04, with a split boiler - still worked as a cooker/heater) - and the s/h Aga we've just put in cost £200 to buy and then £800 to install.
Oil-wise, last year we got through £3000. But that is with it on 24/7, just turned down in summer. Our house is an 1800's converted mill and the 'room' the Aga sits in is 5m x 12m, plus it heats a couple of towel rads and supplies hot water. Only other heating source is a log burner in the front room, 5m x 8m and about 6m tall. No other heating upstairs (except the towel rads), but open ceilings downstairs means the heat just rises.
House is well insulated, and I'm continually improving this.
We do have an electric shower too, that is a no brainer.
We love our Aga, the oven is always hot and ready for cooking. Anything wet, just dries nearby. And every meal is served on hot plates, from been just sat on them while we cook.
But as said, we've a house that suits.