I agree that youtube will completely change the way in which new talent is 'discovered and that this will loosen the stranglehold of the popscene 'mafia': cutting out the middleman - at least in the earlier stages. This is perhaps rather like what happened with Obama in a completely different field.
I dont know anything at all about any of those other artists you mention so I suppose it has to go down to preference and I certainly dont want to say anything unkind about his music. If the number of clicks counts most then he's already 'made' it.