Since my iPhone 5 manages 6/7 hours. (And no I'm not a apple fanboy) 3h is rubbish! My S3 managed just over 4h and i know the Z has a bigger screen and resolution but no excuse for putting small batterys in phones that have big screens and high res.
iPhone is different. It's well knows that iOS devices have better battery life. Lets compare Android with Android - which as we all know doesn't manage power very well ( at least not as good as iOS or Windows Phone ). I'm pretty sure you'll be able to get 4h+ screen time - it depends on what Spectre has been doing with his phone.