We have a Rayburn and an oven & hob. Went for the Rayburn over Aga as it heats all the rads of the house (20 rads) and the water as well as cooking, and you can have one on without the other. It certainly does what it does very well, great for heating & hot water and roasts are lovely and moist out if it, it doesn't dry out food, much easier to keep food cooking slower & longer if that's what you need without risking drying out that would happen with a fan oven.
Whether its worth it for you is obviously a personal decision, to be honest for us I wish we had spent the money putting in a stove and an oil boiler so we'd have an oil-free option for heating, and as there is just myself hubby & baba I don't use it for cooking as much as I could, but it's fab when I do. You couldn't really be without the oven & hob as well for summer / convenience, also handy at Christmas and when you're cooking for a crowd, I grew up in a house with Rayburn & oven & hob, I wouldn't know how to cook for a crowd without all 3!