I have used this phone a lot.i have purchased it from amazon.after using this device for almost 6 months I am going to review this honestly.no complaints I have regarding its sound reception and call quality.the design of the phone is good at this price range.it looks well in hand.the phone is user friendly too.the other feauters of the phone is too good as I have said it is beast at this price range.i have not faced any lagging using this device.at last I want to say that it is truely value for money at rs 5999.go for it without any hesitation.thank you xiaomi for this device at for a reasonable rate.