Ray - I guess that's kinda like waving $20 in one hand and $50 in the other and asking the guy which one he'd rather have. ;)

I've been very happy with the performance of the 420EX, but I don't really have anything to compare it to. I've not used the 550EX. I guess the thing to remember is that the 420EX has no way to control it manually. It's controlled completely by the camera (no LCD). I got the 420EX, because I HAD to have an external flash system and I knew my wife would KILL ME if I spent another $350 on this camera system right now. It was well worth it and performs nicely.

Would I like the 550EX? Do people in jail want out? hehehe