I see most choose to deny Madara..... ^_^
Half of The Rikudous powers are in Naruto and Sasuke, yet Madara easily toys with them this chapter. Even moreso Madara has the power that Kaguya had plus two Rinnegan like The Rikudou..... Imho Rinnegan>Byakugan. To each their own.... This is my list
Madara currently
Kaguya
The Rikudou
Obito
Sasuke and Naruto
Sasuke and Naruto
Indra
Ashura
Hashirama
Itachi
My opinion.... It's just an opinion like everyone else's, but I do however choose to believe wholeheartedly that Madara is the strongest and that some choose to deny him out of bitterness..... Denial as well.....
Kaguya stated to be more powerful than Hagoromo. Let me just get that out of the way first.
Based on Madara's own words, Hagoromo could have the Juubi's Eye if he wanted to as well. This also explains how he was able to give it to Sasuke when he apparently didn't have it.
Hagoromo prior to becoming the Juubi jinchuuriki was at least 50% of the Juubi in terms of power. Secondly, Hagoromo was the complete Juubi jinchuuriki. Madara is missing Yin Kurama, and Kurama is the most powerful of the bijuu. Yang Kurama alone was capable of taking on several bijuu.
Not to mention that Hagoromo created the Moon on his deathbed, without the Juubi's power.
As for the argument that Madara has the Shinju and Hagoromo didn't... Of course he did. If not, then where on Earth did the Shinju go? Did it just vanish? No, he obviously had the Shinju as well.
Hell, even Obito, the weakest of the Juubi jinchuurikis, had the Shinju.
Hagoromo > Madara, and since Kaguya > Hagoromo, Kaguya > Madara.
This is ABC logic, and it does work, because I am speaking in general terms, not in 1v1 terms.