I could clearly see better and brighter colours from the Samsung Galaxy S over the iPhone 4, I didn't really notice this "Retina" thing. I had to squint and look closely before it came noticeable, so as impressive at the high resolution is, it makes little difference to everyday use.
Must admit that the Super AMOLED screens make me a little jealous. It'd nice of Samsung to increase there production so other manufacturers can use this great technology.