If you position trade, then please participate in this poll. Also, if you trade intraday, then please be sure to participate in the intraday poll: http://www.elitetrader.com/vb/showthread.php?s=&threadid=176246
In my opinion in principle entering on pullbacks but not on breakouts assures that one gets every losing trade of one's method because every losing trade pulls back by definition and one misses the winners that don't pull back. Entering on pullbacks has its place such as in automatic investment plans or when bargain hunting. If I had to choose one of the two it'd be breakouts.
I trade individual stocks and I enter on a breakout that occurs in the pullback, speculating that the pullback is over and the uptrend is about to resume. I place my stop at the bottom of the pullback so if I'm wrong I'm quickly stopped out.