A free ninja or one that costs 20k. They both do different things but overall I'd say kushina fully breakthrough is better. Scaling, removes immunity, heals. Shizuka 4 star is good for different reasons but if you really want to know which between the two is better.....

Itachi frags for the cheapest? Usually konoha great tree cause you c*e the 7 daily free spins to get points and there are a bunch of other goodies to get along the way.