So, I've noticed that a lot of people throw hatred on some of the Robot Masters from the original series, particularly ones like Sheep Man or Pump Man - both Robot Masters I thought looked pretty cool. These guys get a lot of hate from fans, though, and it led me to realise that, despite how much we adore the older ones, there's no denying that older R.M.s looked kinda ridiculous too. I mean, we hate on a guy shaped like a baseball, but we let the guy with scissors glued to his head slide?

Personally, I really like the underdogs in Mega Man. I loved Dust Man and Gyro Man, and Sheep Man and Pump Man are my faves from MM10. What R.M.s do you guys think are underrated by the fans?

My Faves:
Ice Man
Heat Man
Needle Man
Dust Man
Gravity Man
Knight Man
Spring Man
Aqua Man
Magma Man
Sheep Man and Pump Man

I agree; the RMs in general are just under-appreciated. If you ask me, I always prefer them over any animal-based Maverick. I don't know about the Four Guardians, though...
Anyways, my favorite RMs are as follows, in no particular order:

Flash Man
-Definitely not liked much by people; due to a particular manga, Flash is much often seen as a psycho. =( He has such a cool design and power, though!

Napalm Man
-Favorite bomb-based guy ever. Looks as a human tank! And fighting him is a blast. (Kinda walked into that one.) And, if anyone asks, he's blue. Not purple.

Gemini Man
-Gemini Laser + Cloning == Amazing.

Knight Man
-Don't see many knights in Rockman/Mega Man, and when they're there, they're awesome.

Yamato Man
-Knight Man's counterpart, also cool.

Quick Man
-If you have to question why anyone likes Quick Man, then we need to talk.

Star Man
-The looks, the weapon, the stage: everything is right about this guy.

Shadow Man
-Who can say no to a ninja?

Sword Man
-We were waiting for a sword-based guy, and we got him.

Fire Man
-Classic flame guy. Never, ever call him Torch Man. Just don't.

Heat Man
-Another classic flame guy. Atomic Fire, anyone?

Now, you may notice the lack of RMs from 9 and 10; I have yet to play those.