He is an excellent ninja... but of ninja of his tier he is amongst the easiest to get.
There are only 3 possible rares in the Sage Treasure, 2 of them are *y prizes but you got a 1/3 chance to get him every 60-ish pulls.
That being said Sage Naruto from sage treasure is about 15k ingots if you get him within two pulls, the stars event's cost is similar (or slightly cheaper)... then again you could get lucky and get Sage Naruto as your first Sage Treasure rare.
Really, he is a good ninja. You should get him eventually, how you want to do it, through events or through rare pull is up to you.