6tail naruto (4*) is leagues and miles stronger than Ay, it is not even close. It's like comparing regular 1010 to a 5* gnw 1010; that big a difference. Ability to brute force through healspam teams is a pretty big deal, something Ay can never dream of doing.

Tendo is strictly for 3v3s. He is amazing at 3v3s, but really awful in 1v1 combat. Hashi is good in 3v3s, and useable in 1v1s for specific lineups; but not any better than regular rares like mei or danzo for said 1v1s.

4tail naruto (3*) is still quite decent, and is definitely one of the strongest ninjas. (It also gets me quite a number of instant forfeits in matsuri ;P)

As far as super rares concerned, Ay is probably the worst one. He is only good at stomping much weaker players (or punching the coin cat), and not even good against equal power players in the current meta.
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Regarding the price.. pretty sure Time limited shop is the worst place to buy chakra naruto. He costs something like half as much per fragment in other events where he is available...