I believe that the Retina Display does win with the sharpness and smoothness. But the question is if they are commenting about the rendered fonts or the pictures themselves. If we are talking about pictures, we have a huge problem. Pictures can be gif, png, jpg, tiff, and what else... plus we have to think about the display rendering of the iPhone OS itself. It gets messy. (to be fair, so does the Galaxy S)
But I think Engadget did a very good job with the pictures and videos. It's real data this time than the theoretical stuff we have been throwing around. IMHO, Samsung Galaxy S is FTW!

I wrote about comparisions and screen stuff in
http://careace.net. Just say'in hi guys! (
http://bit.ly/aqae7S)