Boku no Hero Academia

Alright, time to answer the question: which one is more powerful, All for One or One for All? One for All is kind of unmatched physically, but All for One's power of combining and stacking quirks of is versatile as fuck.

They're both stacking quirks. One for All gets more powerful with each inheritor and All for One gets more powerful with each quirk acquired.
As n approaches infinity they both become infinitely powerful.

Yeah, but while One for All only increases the power when it passes from people to people, All for One can be increased by stealing quirks more frequently and is much, much more versatile. Meanwhile, even if One for All is absurdly more powerful with each holder, it's all strength/speed/resistance.

Why does she wants to be a mother so badly? and why can't i be the dad???

All For One is stronger. He can steal all quirks and create Nomus. Steal the quirks of Ectoplasm, Mt. Lady, 13, Eraser and Shouji, put them all into one Nomu and he has an army of giant Nomus with 1000 eyes who can erase all quirks and destroy all cities with their 1000 black hole hands.

Why did All for One lose twice then?
Plot armor?

One for All = polygamy.
All for One = rape.

I think that it was plot armor, yes. The power of stacking quirks is fucking versatile and even in the fight with All Might, he decided to go full chimp and met him head on in a duel of strength when he could stack quirks like pyrokinesis and shit.

In the long run I think One for All is stronger. Seen by how only by Toshinori's generation is he able to beat All for One 2 times.

His predecessors all lost. One for All continues to stockpile strength, speed, endurance. But All for One is more versatile but may lose since they are BASE quirks.

Either it's plot armor or some kind of plan AFO is plotting. AFO can fly and deliver his shockwave attacks endlessly, but he decided the best way to kill All Might was to float 3m above the ground and start a fist fight.