Great smartphone; No problems with it after 1.5 years.
I've had this phone for a year and a half, and it's still working perfectly fine.
It might feel like a cheap build at first, but it makes up for it by being lightweight and it is quite durable. I've dropped it several times, which leaves scratches in the corners, but nothing permanently broken.
I've used it in the rain. It is truly waterproof. And there is no lag in applications, even though I've nearly filled the data. The camera is decent, though I wouldn't say it was the best, especially the front camera at night.
I like having the back button and application button along with the main button, as it feels more intuitive and gives more control and customization options than with an iPhone's solitary button, and doesn't use up any real-estate for the screen.
Possibly one of the most useful things about this phone is the multi-window option, which allows the use of two applications at once (like music and google maps, or youtube and messenger). This is so convenient and I use it all the time. Excellent for the multi-tasker or the multi-media consumer.