I'm just finishing my first week with the Z3 D6603 and I've got to say, it is a great little phone. Light and thin in the hand, it is very zippy and 0 lag. Great screen, great sound and a very good camera. Battery life is OUTSTANDING! I've never been able to go a full day without charging before! I have had absolutely no problems or hiccups of any kind. I recently came from the Galaxy S4, HTC One M8, Galaxy Note 4 and the OnePlus One. So far, I would choose it over any of the others.