I actually compared my friends Mi3 to My S4.
yes, it's absolute stunner for the price. But definitely a downgrade for all those using a flagship category phone. The LCD is IPS alright, but is not among the bet IPS displays. When compared to the S4, it was a bit dull and the brightness, saturation and contrast levels were no match to the Amoled display. Heck, my mom's XoloQ1000 has a brighter IPS display than the Mi3.
Now coming to the built quality. It may be a well built phone, but it does feel like a delicate piece of equipment. Something about it always keeps reminding you to use it carefully and not to drop it.
Size is almost as big as the Note 2 in dimensions and yes it's not a one hand phone. There is a lot of unwanted bezel around the phone. That's good if you game a lot but otherwise it's just wasted space.
Compared the audio quality in headsets and on speakers. The S4 totally won this department by miles. The Mi3 loudpseaker is not at all loud and is something to be used only for ummmm.. nothing! The S4 on the other hand allows me to have a really clear speaker phone call and is great for watching youtube videos.
Where it excels though, is the pure processing power and the good battery life it possesses. The camera is really good in all the lighting conditions. And you cannot ask for anything more at that price!
Great to see such offerings coming to India. Although it has hugely affected the resale value of the Premium phones. And Must I say, it packs the hardware and the software to do it all, but just lacks the fineness of a Premium phone.