I am 1 of those died in the wool fans(400 +days). Yes it does tend to be an older clientele, but we prefer that.
I don't have a lot of experience on other cruise lines, but we have tried some and always come back to HAL. You can not beat the service or the food anywhere. IMHO. As far as night life not sure what you are looking for. Shows every night and the bars and casino open till the wee hours.