Depends what cut it is? If it's diced neck of lamb then yes, cooking in a sauce (curry?) for a very long time would be lovely. If it's rump or something, then a fast cook (i.e. on skewers) would be better. I don't know much about lamb cuts as I rarely cook it, but I know as with beef it totally depends on the cut. You wouldn't recommend someone get a rump steak and cook that in a stew for 4hrs would you?
(Apologies if that sounds very negative, I'm only trying to be helpful! My pet hate is someone using a really lean/expensive cut of meat in a stew and wondering why they end up with what resembles dog food at the end of it!)