I am using my lenovo s660 since 3 years ago.
This product has been working very forceful. I am totally satisfied about this lovely product. This android phone has spectacular version kitkat 4.4.2 . It has large ROM size upto 8GB mine a lot. It has 1GB RAM ( Random axis memory ) . This product has 4 core cpu which has never hang the phone. About expandable external memory upto 32 gb. I spend my lot of time whith them. 8 mega pixel real camera capture not only good photos but also clearly record video and about front camera the brightness has poorly. So it has times to upgrade. The real fact is it would be upgraded in to 4G network. It makes vibrant in sound quality so I will suggest you that improve the sound quality in next version. Thank you.