I got my replacement unit from Asurion yesterday and it is a 004 HW [SW 3.20.651.3 ; activated 12/14/2010] and the phone was BNIB.
My neighbor also has an Evo [ HW 003 ; SW 3.29.651.5 ; activated 10/15/2010] ] so when he came over tonight, I compared the two in a dark room, both on the same wallpaper, same brightness et all ..
Using the ' Power Control ' widget, the 004 screen is warmer [ whites are a bit yellowish ] and the 003 screen is cooler [ whites have more pop and are milky in color ] Colors seem slightly better [truer] on the 004, but blacks were slightly more inky on the 003 IMO. Viewing angles are same on both.
Using the ' Power Control ' widget, and adjusting the brightness thru it, the 004 gradually faded, while the 003 changed brightness instantly.
The 004's power button is slightly raised in comparison to the 003's. The volume buttons are about the same, or maybe a hair higher on the 004.
No light leakage on the 003, while the 004 has some right below the ' home ' icon. It doesn't bother me enough to warrant an exchange [and I don't wanna risk Asurion sending me a refurbished unit! I had to almost fight to replace the POS refurb they sent me initially for a brand new one!!
Battery life and touch screen response are about the same on both!
I haven't played with the camera, so can't comment on that yet!
I took some pictures and will upload'em tomorrow for everyone to view and compare.
Feel free to ask any questions