Karbonn w4 .a very very nice product.one n only windows based phone in karbonn family.
reviws after 5months of use.
1) is has really really good battery backup as a smartphone.(including last 4a day after high uses i.e listening some songs.whaspp continuing.n moderate surfing)
2)in terms of camera its also very very nice as those who crtisises it have not used camera well as one can adjust various effects according to their need such as iso control, exposure compensation, resolution etc.
3)in terms of touch n display again thumbsup as we dont want to push hard to type I mean is really smooth touch n display is also goood as no one has extraordinary eyes.
4) in terms of gaming n hardware .its really really nice as I myself had played temple run2 n chess both for more than hours n n phone warms up little a bit nn that is normal.
5)those who say that phones heats up may have purchased a defecetd one
6)1+ that it has removable battery .yes removable.!
7)ultimately its really really a good product .
n bear in mind b4 using/trying this smarty I experinced lumia 640 xl n samsung core 2.
I hope this will help u reader.