They will have a lot of fat on them, so if you want decent mince tell your butcher to chuck away most of the fat. (a decent butcher will do it anyway, but I am not that pleased with my mince from my last batch of mutton sheep
). Taking that into consideration your meat yield may be a bit less in % terms compared to lamb.
You can always render the fat and make soap from it...
But you should be able to make great curry from the cubed bits, and we find the legs roasted (following HFW's recipe) taste divine.