Display: Good display irrespective of whatever the numbers say. Certainly not the best but keeping the price in mind its excellent. The screen is a dust magnet and catches fingerprint like anything. Nevertheless its a great display for this price bracket.
Performance: Not the blazing fast and I found some lag while moving across the apps very fast, say using 2-3 apps per minute but not something unbearable and for normal operations its fast enough. Played some small games and worked fine without any lag. Decent performance I would say for the money Ive paid.
Call: I opened the box inserted the sim, made a call and Surprise! None of us can hear! Not expected from a phone at least, I mean this is the basic functionality of the phone! Come on Microsoft! After a bit of Googling came to know this can happen with dual-sim and WP 8.1 combination. Solution is to update to latest firmware. This does solve the problem but still not expected. 1 star removed.
Camera: Decent daylight photography and nothing more to write home about. Without flash does not work in low-light condition.
Cortana: By default its not enabled in India, but you can by a small tweak. Just Google it. This is the new Personal Assistant from Windows and reply to Google Now and Siri. This is in beta version but way behind than competition. Needs to improve much. However does the basic work fine and understands Indian accent well.
Battery: Better than competition I would say in this price range. Like any other Nokia phone the battery here is also very good and only drained about 50% after 5 hours of heavy usage over WiFi. Satisfied!
Windows 8.1: Nice one and very close to Android or iOS for that matter. Yes it lags apps in the store but basic apps are there. Floating tiles concept is very handy once you get used to. Action center, Cortana, Swipe keyboard are nice features. Running in a 512MB RAM without lags means a lot. Im impressed with it.