This is the best phone on this price. Key features that makes this phone worth are
Great battery life(Removable battery)
Very classy camera performance(8 Mega pixel Primary camera & 1.6 MP Front camera)
Good display(720x1280 pixels)
Design is also delightful
But after installing a lot of apps, RAM available for apps would be very low. Due to this the phone can start to get hanged after a few months of usage. It is powered by a quad-core 1.5GHz MediaTek MT6589T processor which makes the performance much better during the normal use. 3D gaming performance, however, was less than perfect. There were heating issues but after a few updates its comparatively low now . The Redmi 1S comes with a WCDMA slot for 3G data and a GSM slot for 2G data. Both slots aren’t 3G enabled. It takes more than 2 hours for full charging and it also doesn’t have a back-lit Keyboard, so its hard to find the keys in the dark.
The SAR value for this phone is 1.2W/kg, much less than the allowed max of 1.6W/kg in the U.S.A.
I have mainly explained only the bad side of the phone because; for this price I think all the features and properties other than those mentioned above are better than today’s average smartphones.
Overall its the cheapest with the best features.