Well, no one has seen what the world looks like from the perspective of one who possesses the rinnegan... Several times in the Manga, the Sharingan is mentioned as the most treasured visual jutsu. It has always been more feared than the Byakugan. The So6P used the rinnegan and gave birth to ninjutsu (That includes the Sharingan). These are all facts mentioned in the manga, not fanboys/girls arguing over which one they think is best. Ultimately, the power of any jutsu lies with the intelligence of the user. So far, Itachi has proven to be one of the most intelligent of ninja... I can't imagine how different your view of the rinnegan would be if Itachi used it.
Personally, I don't care which one is better or not, but I wouldn't say the rinnegan sucks since we don't even know what the user sees. :shrug: