I just got a Version 004 today, and there is some light leakage. My last 003 had none whatsoever (till I cracked screen). However the WIFI is WAY better, I get much better signal in my bedroom (my router is in my basement) than I ever have with my two previous 003's. The wifi signal is as strong and sometimes stronger than my laptop. Phone came preinstalled with all the updates.
The 004 screen seems to be Epson, it's the coolest and least blueish of the 3 I've had. I just got it today so I'm not sure what other benefits it may have. The light leakage doesn't bother me. Thought about an epic because the evo screen breaks so easily, but I loves me some evo.