Personally, I think skelebots got the short end of the stick. The extra height makes it so much easier to be hit, and also makes you unable to go through certain narrow corridors in caves that a human could normally go through. The generally higher health and other stats is a good plus, but I find that the parameters for each character doesn't really make that great of an impact.
Heat and cold protection aren't very important, as a coldsuit is very easily made, and a heatsuit just takes a bit longer, as lava isn't too hard to come by.
While the no-ghosts thing is definitely great, ghosts really aren't too much of a threat, considering how much health they end up having. Even during a boss battle, you could probably go to a corner and easily snipe off the ghost before returning to the fray.