I think the person who gives hype is more important than hype itself.
For example, if a kage level shinobi says a ninja is "strong" and a fodder ninja says the same, more importance and respect is given to hype given by the kage level ninja.
Orochimaru said sasuke's genius makes his genius look pitiful. [which is a very big hype considering orochimaru is one of the most genius ninja out there]
Kabuto said sasuke can use the best attack technique. [kabuto is one of the most knowledgeable ninja in the whole world.]
Zetsu said the same as above.
For tobi, sasuke could be more useful than nagato.
Itachi was surprised after seeing sasuke using susano.
Tobi was impressed by sasuke after danzo fight.
Naruto himself said that he is dumber than sasuke and at one point, admitted inferiority towards him.
Kyuubi said his chakra was as strong as madara.
I can keep going on and on but i know nobody is going to read huge wall of text