Here is my quick review after 4 days with my GS4...
First, I really love the new phone. I upgraded from the GS2 and glad I waited and did not get the S3. Now it really feels like a legit upgrade.
The screen is just so beautiful. The Apple retina display is great, but the SGS4 finally overcomes it with the 1080p Super AMOLED display. The images just seem to pop, and watching videos in HD is a real treat. Finally, a phone that I dont mind watching videos on besides youtube.
Camera is fast (like shutter speed is redic fast), which is a nice to not have to wait to take multiple photos. The quality of the pics is awesome, and really I really enjoy looking at them on the phones screen.
Call quality has been great and I have had no issues up to this point.
Thats all for now, more to follow...