First of all there is no difference with K3 except for an extra back cover provided with a small speaker.
Its really embarrassing that a music edition phone that costs around 13000RS comes WITHOUT a HEADPHONE.
Regarding the phone:-
The charging time is very long, takes min 3 hours to get fully charged
The basic use of proximity sensor is lacking, the phone doesn’t lights up automatically when we ope the flip cover.
The 3 keys in the bottom is NOT LED back lit. Its really difficult to use in landscape mode. Becomes much harder in night.
The notification pane icons can’t be customized.
The default applications cant be uninstalled. Even if its disabled it will ask you to update. This will surely irritate you.
The cam quality is not upto the level . Especially in low light conditions. Also there is no image size settings
The side keys are not smooth. you will find it a bit uneasy to lock and unlock.
The phone doesnt give the full power of a octa core processor and 2 gb ram . Its lagging some times . especially when you open recent apps