ASUS is one of the well known identity in field of Motherboard fabrication. I have Asus laptop and using that in my professional field and happy with their performance.
Its just a great news when I heared about grand entry of Asus in the field of smart phone. I ORDER Asus Zenfone 5, without thinking mush as it has many great feature like 2 gb ram 16 gb internal memory, preeminent camera with auto focus and flash, with competitivr price range. I use this phone from last year .This product dont even lag even for single time.
I advice you yo go for it.