Well he's definitely wrong.
Hmm...
I don't know what's being done different. I have my Vita and I can definitely vouch for a 4ish hour battery life. Maybe because I'm not using the touch screen too much? Would touch screen drain batteries faster?
I've heard multiple reports saying more in the 4-5 hour range. More people have said that than 3 hours, which I've only heard from Engadget, Gizmodo and Giant Bomb. Who knows.