Different shinobi are strong vs different shinobi.
Apart from that, I would say in general that Kankuro is a stronger shinobi than Temari.
I am surprised how many of you say Temari.
Why do you think she is a stronger Shinobi than Kankuro and more fitting as a leader than him?
Temari only has her ranged wind jutsus and attacks with her fan and that is it.
If the target is a Fire user, what is she gonna do?
If the target is fast, good in taijutsu and can get in close range, what is she gonna do?
I find her very limited and fragile for a jounin.
She lacks abilities to cover her weaknesses.
Kankuro is more versatile.
He has puppets to help prevent people from getting in close range (his weakness) and tricks to swap himself with his puppets. Even in close range his puppets can assist him.
With Crow, Black Ant, Salamander, Sasori's parents and Sasori (his puppet body), he has a wide array of puppets for all kinds of situations. Mechanical Light Shield Block is a pretty good defense too.
Poisons can be a strong ability, which Kankuro uses too with his puppets.
Kankuro has shown his leadership skills in the war, with the leading of the assasination squad.
He seemed like a competent leader to me.