wow! this is a truly stunning piece of art work. rainbow dash looks positively bad ass. (or bad Flank). the smoke in the background is a nice touch. I really like how this is colored, as well. How you portrayed her in this kind of reminds me of the soldier and Heavy weapons guy from Team Fortress 2.
Allow me to add a little bit of constructive criticism; the wing looks as if it's a little bent out of shape, the cutie mark could be a bit bigger than it is, and the cigar looks a little bit like a candy wrapper rather than a cigar. Other than that, the drawing is amazing! keep up the good work!