I am using this phones from 9 months and I had never seen lac or bug in it. It is running very in smooth manner without hanging and is very easy to use because of its MI UI version. Because of Mi UI version the phone gets take good pills with this simple way to run it. Xiaomi is one of the India’s biggest company actually in number first company for the production of mobile but they get down on their services because the charges for their services is so high like my phone’s screen get cracked and I need to repair it but the charges of this particular screen is 3000 which is so high as compared to its price and other companies. So I am recommending you that if you want to buy this phone you should have to cover it with glass and back cover which helps you to protect it but if it damaged so you are responsible for this and you should have to pay high prices for its services