I prefer the look of the Mk2 switches, but the Mk3 one's have better "feel". I swapped as I got fed up of turning my main beams on when all I wanted to do was flash someone (ahem!).
...The funny part of the above is that a day after fitting the Mk3 stalks, smoke started billowing out of the steering column - The Mk3 switches had melted from a short circuit. Cue ebay refund and putting the Mk2 stalks back on!!