Not a must buy. here is my pros & cons.
Pros: -
The best thing about 6s is 3D touch, it is very useful, for now only few apps supported that, it is also useful for saving contacts from a msg and many more.
The touch reception is fabulous, web browsing & playing games is a treat on this device without any lag.
Camera quality is good, not best, daylight captures are very good, in low light it struggles little bit.
Sound quality in speakers & headphone is very good. Call quality is superb.
Battery life is decent.
Cons: -
Display quality not upto the mark. Being a 4.7 inches screen it gives only 326ppi, where as many android phones with a half price of it gives around 500 ppi. Little bit disappointed.
Price is too high, not affordable by everyone.
No expandable storage. Even 16GB costs around 50000 /-.
Camera quality is similar to a 30000/- android phone.
Too many restrictions. You can’t download any music or videos direct on this device.
Verdict: - Not a must buy or not a must upgradable from iphone 6, 3D touch is not necessary. Its 16GB model price drops from 62000 to 49000. Wait for iphone 7.