Happy Everhot owner here. Grew up with cookers from Rayburn, Stanley, etc.
Everhot think slightly cheaper to buy than Aga. Also much, much cheaper to run than Aga partly because Everhot better insulated, but for that reason Everhot throws off less heat.
Good in summer, because you don't have to switch Everhot off, though you can turn off ovens and hotplates as you wish, whereas Aga gets hot enough to drive you from kitchen. Conversely Everhot will not do as good a job of warming cold + draughty farmhouse kitchen as an Aga. You pays your money (literally) and you takes your choice.
Use Everhot here in modern well-insulated house, is effectively only heat source for large open plan living/dining/kitchen. There is one radiator, but is behind sofa at one end, and not really big enough, so previously needed central heating on frequently to keep that space warm. Now Everhot keeps it cosy throughout day, all year round, and no longer use central heating during day since the Everhot came (only quick blast last thing at night to warm up bedrooms). Just had very substantial refund from gas company as a result, as using much less than they expected.
Everhot customer service is very good, reports say dramatically better than that of Aga, which was taken over by US company some years ago. Everhot Facebook group gets steady flow of former Aga owners who can no longer bear running costs, or frequent breakdowns / need for servicing, or lack of care for customer. Plenty of former Aga owners on there.
I grew up with range cookers, knew what I was getting into, plus it worked for our specific situation. If you're not sure, Aga or Everhot is huge upfront investment without clear return. Cost-wise, doubt it would make sense. Kind of a lifestyle thing, though Everhot does cook nicely and the always-on aspect (and the grill!) is surprisingly handy.