The Best Robot Master EVER is Galaxy Man, ranked 1st out of 110.
The Second Best Robot Master EVER is Napalm Man, ranked 2nd out of 110.
The Third Best Robot Master EVER is Snake Man, ranked 3rd out of 110.
The Worst Robot Master EVER is Venus, ranked 110th out of 110.
The most popular Robot Masters of each game are:
Mega Man (& Powered Up): Elec Man, ranked 9th
Mega Man 2: Air Man, ranked 18th
Mega Man 3: Snake Man, ranked 3rd
Mega Man 4: Pharaoh Man, ranked 5th
Mega Man 5: Napalm Man, ranked 2nd
Mega Man 6: Knight Man, ranked 6th
Mega Man 7: Shade Man, ranked 10th
Mega Man 8: Tengu Man, ranked 41st
Mega Man & Bass: Burner Man, ranked 14th
Mega Man 9: Galaxy Man, ranked 1st
Mega Man 10: Nitro Man, ranked 11th
Mega Man 11: Blast Man, ranked 12th
Mega Man V (Game Boy): Jupiter, ranked 24th
The least popular Robot Masters of each game are:
Mega Man: Ice Man, ranked 105th
Mega Man Powered Up: Oil Man, ranked 106th
Mega Man 2: Flash Man, ranked 87th
Mega Man 3: Spark Man, ranked 91st
Mega Man 4: Ring Man, ranked 117th
Mega Man 5: Stone Man, ranked 89th
Mega Man 6: Wind Man, ranked 92nd
Mega Man 7: Burst Man, ranked 102nd
Mega Man 8: Aqua Man, ranked 109th
Mega Man & Bass: Dynamo Man, ranked 104th
Mega Man 9: Magma Man, ranked 101st
Mega Man 10: Chill Man, ranked 70th
Mega Man 11: Bounce Man, ranked 108th
Mega Man V (Game Boy): Venus, ranked 110th
The most popular member of the Genesis Unit is Hyper Storm H, ranked 40th.
The most popular Mega Man Killer is Punk, ranked 17th.
All games, ranked from most popular Robot Masters to least, are:
Mega Man 10, with an average ranking of 39.9
Mega Man 3, with 41.0
Mega Man 2, with 49.4
Mega Man 11, with 51.3
Mega Man (original six only), with 51.7
Mega Man 6, with 52.4
Mega Man 5, with 52.9
Mega Man & Bass (full set), with 53.0
Mega Man & Bass (King Numbers only), with 53.8
Mega Man 9, with 55.1
Mega Man 4, with 60.4
Mega Man 7, with 64.0
Mega Man Powered Up (full set), with 64.1
Mega Man 8, with 69.1
Mega Man V (Game Boy), with 72.1
All games, ranked from most consistent Robot Masters to most divisive, are:
Mega Man 10, with a ranking range of 59
Mega Man 8, with 68
Mega Man 2, with 69
Mega Man 3, with 82
Mega Man 6 and Mega Man V, both with 86
Mega Man 5, with 87
Mega Man & Bass (both full set and King Numbers only), with 90
Mega Man 7, with 92
Mega Man (original six only) and Mega Man 11, both with 96
Mega Man Powered Up (full set), with 97
Mega Man 9, with 100
Mega Man 4, with 112
The Mega Man Killers ranked higher overall, and more consistently, than the Genesis Unit.
...and Quint is still terrible.