Good stuff. Great job with the depth on the one with girl and rifle. I've spent a lot of time drawing with the mouse since i was young but as once the laser mice came it didn't have the same feel, but i got used to it. But yeah once you get a drawing tablet, it's a whole new world. I Just got a intuos pro 4- Have not even seen a Cintiq irl yet but i'd imagine that one would be a total bliss to work with.
Yes, I think that you maybe do get a kind of special rough feel when using the mouse... also a bad elbow. I really liked the murderous fantasy-drawing you did with almost no anti-aliasing. especially the black an white studies were great. I should write a comment on the post instead :)