I have been using this phone. I really like the build quality of the phone. I have owned Huawei U8800 pro, Lenovo P770 previously. Redmi 1s is the only phone I did not take to a service center for issues.
Recently I bought Meizu M2, but unfortunately the glass over the screen broke in a fall. Now again using my Redmi after a gap of 20 days. After MIUI 7 update its even better. There is occasional lag in some apps, but it is not to a disturbing level.
I really appreciate xiaomi as they just did not neglect the old devices for updates. Even if I had to take it to a service center for some issue, their service centers are better than other brands as they have many exclusive service centers. For the price I paid I couldn’t have had better phone.