If it didn't burn eyesight or drain stamina, Kamui any day.
If I could fuse ANY 3 Shinobi's power as JUST power & prowess it would be Kaguya Arc Obito (for Kamui & MS techniques), Edo Muu (for flight, invisibility, dust release, fission & immortality) and Juubi Hagoromo (for Rinnegan, Rikudo chakra to make Kamui & all of my other abilities more powerful, linked vision with my multiplied forms & Mokuton)