I'm at Radio City Music Hall checking out the Samsung Galaxy S4. Tell me, have you seen the Galaxy S3? Then you've pretty much seen the GS4. There have been a few cosmetic tweaks, and a spec bump, but it's mostly a "Galaxy S 3S."
The screen is probably the biggest upgrade. It's been fitted with a 5-inch, 1080p AMOLED display, and it looks gorgeous. The viewing angles are perfect.