I bought the Asus Zenfone 2 (ZE500CL) purely because I was drawn by its Intel Atom processor and it seemed like a decent device.  The one thing that really got to me was the woeful battery life.  I had the choice of getting the ZE550ML one which had a bigger battery (2500mAh vs 3000mAh). However, it has a bigger screen and houses a quad core processor.  I don't need a quad core phone and the 5"