I am one who likes to use "good" Pokemon. Nevertheless, looks do come into play when I choose Pokemon for my team, but it just so happens that Pokemon that I like based on looks I also tend to like based on stats. (Umbreon, Arcanine, ect.)
But no matter how much I like a Pokemon based on looks, if it can't take a hit, or at least deal some damage, (I prefer walls and tanks to sweepers so defense and special defense are big factors when I pick out my team.) it gets boxed, no matter what.
For example, if I can find a good Fire type (or maybe a suitable Ground type because I've already got a decent Tranquill to take out Grass and Bug types) I might trash my Pansear. Even though I am not bothered by the design, and it can take a hit, it does WAY too little damage, even when I got rid of Incinerate for a different fire type move that was more powerful, it still barely does anything. Even when I've used Work Up it still can't do anything. The only reason I've kept it as long as I've had is because it can take hits decently.