Out of all of the new Hero Factory villains, Nitroblast has the most consistent visual appeal from all angles, in my opinion. To my surprise, the use of a red main body skeleton in conjunction with the red legs, upper arms, and mask, allow for a more finished appearance from behind than the other villains (and heroes, too).
The mask is the whole head on this one, attaching directly to a socket joint piece, but I think that's well-executed and doesn't detract at all from the appearance of the piece. I have a mild obsession with his eye piece, a Baraki eye in what I believe is a new color for that mold, sort of a radioactive green -- I don't know the official name for the color, but it's not a normal trans-green, nor is it traditional neon green (which is actually more of a yellow). Whatever it is, it's mesmerizing and I want lots of them.
The sole miss with this figure is the left arm, which I think is over-engineered and much too stiff for its own good. The jet-powered flame thrower isn't heavy enough to warrant this much friction in the joints. The LEGO Hero Factory website shows that the inner arm piece should to be detatched when needed, and the open socket joint is supposed to represent a "plasma blowtorch." The instructions, though, have you assembling it to the main arm, and in this position it fits well and obviously was designed to be assembled together. The box art also shows it fully assembled. I get the feeling LEGO realized the arm was too stiff and tried to rationalize it after the fact. When it's separated as shown on the site, it looks completely unfinished and silly. "Plasma blowtorch?" Please.
Other than the arm, though, great set, and a cool look with some very exciting new pieces!