The second I learned this trick, many years ago, I've used it in everything. The argument that it's "slow" is ridiculous. It's like using while(i--) instead of a for() to shave 0.0000001 milliseconds off your javascript loops. Just admit you have OCD and move on ;)
I'm fairly disinclined to trust web designers on browser rendering performance issues anyway. If it were that big a deal it would be in CSS optimization code somewhere, but it clearly isn't.
