imo, the profile is a very maintenance free hub, just wack it on and leave it :P
whereas with kings, you have to service them every now and then, plus have to tighten the cones etc...
one of my friends kings is still coming lose after like a year! :P
im not saying a king is any worse on the engagement strength side of things, it just requires a bit more love.
oh and the axles in profiles dont snap :P"