Gear Addict, from what I've heard they taste pretty much the same but have been told by some people its better to just crack fresh eggs as they are supposedly the better option due to being, well fresh?
I personally just use the biggest eggs, jumbo size, as I find the egg yolk is almost the same size regardless of egg size and a bigger egg generally means more white IME. Crack em open and throw the yolk between the two halves letting the white fall out onto the pan.
I don't really have any desire to get egg whites in a carton.