ems and rinnegan is not about proof its about that they both have benifits a neither is really better then the other
ems has all the abilities of the sharingan wich is reading and oredicting movement copying jutsu and influencing the enemy like kakasi vs zabuza then it has amaterasu and tsyukuomi and susano and with susano u can use the magatama move used by itachi it has amaterasu bullets and more that sasuke hasnt even shown yet
and rinnegan can absorb jutsu and attract and repel the opponent it has linked vision wich dosnt help really if its used by jus one person but still its a bonus u can suck out souls if u can get ur hands on them long enough but its not instant tech as shown with tobi vs naruto it can summon but so can everyone else the only reason nagato summons had rinnegan was because they also had chakra rods so the summons must be preped but if they are bonus it can revive ppl who were dead a short time but again if the user is one person and dies it dosnt help at all
so as u can plainly see they both have bonuses and if u cant see that then ur jus a fanboy of the rinnegan also notice a few of the rinnegans moves arnt that helpful if ur using it jus by urself and not the the 6 paths of pain which is how madara is using it