Samsung Galaxy S4

I am seeing lot of issues with S4. already went twice to samsung service center:

• Battery drains

• Camera lags and become irresponsive after some time

• Video recording hangs

• becomes very hot if lagging or hanging within minutes.

Used S2 and Grand, but never faced any issue with Samsung Products. Highly disappointed. and the main issue - This phone heats up much and battery gets discharged so fast, 2600 Mah wont even last long for a day