Tobi, Nagato was his pawn
It's a tough choice. I think Tobi because Nagato was a pawn, and you never know what Zetsu recorded. As for Madara: I think he's still trying to learn some of the techniques, or just doesn't want to show us any Rinnegan techniques. I just know Tobi seems to know everything. xd And just because they had something for the longest doesn't mean they know the most about it.
I want to say Madara because probably ate cake with the sage of the 6 paths in the after life
true storyBlaze Release lol
Nagato... It seems like both tobi and madara were counting on Nagato to revive them with RinneTensei..
Maybe they werent able to master Rinnegan the way Nagato did
Or maybe he was their tool. Who knows?
Obviously Madara!
He knows well to use it even he didnt use them before. You need to knowledge about them if you'll use. How could you use paths or another powers? He obtain this power, it is a really big deal. He was able to gain that power after So6P,no one else other ones taked from him/he gave them and i think it needs knowledge U_U even he planned to revived himself by Nagato.