I used to make Margaritas in the blender. Not too bad, but the ice chips were uneven and would sometimes clog the straw. Then I bought my wife one of these. That's right, I bought it for her! Stop laughing! Now! Hey, I heard that snicker, Liz, knock it off!
Anyway, it makes great Margaritas. The true secret is to use enough tequila. Don't even think about pouring it in your gas tank!