Other than the 5 hours, consider yourself lucky. You will get both status miles on UA AND USair. Just write a letter to UA explaining that your flight was canceled and what UA did to reaccomidate you and ask that your account be credited for the canceled flight (as well as nay other connecting flight(s) they caused you to miss). There is a certificate specifcally for this purpose that you can get from any UA counter agent (I keep a supply in my travel bag). So SMILE and enjoy the extra status miles on USair...
(BTW, "mecanical" or pilots????? I WONDER!!)