dear sir,

in my experience Samsung mobile phone always have defects.
Not in all but only in smart phones like Samsung galaxy s2 galaxy ace e.t.c. the main cause is that the combination of software and hardware is not flawless.like apple, Nokia and LG did.even you can experience when using Samsung smart phones and others like Lg, Nokia, blackberry, Apple.mostly in Samsung smart phones it have lags and bugs.

In my opinion you can have Nokia,HP,Apple,Blackberry,Sony Ericsson e.t.c But Not I phone 4s cuz it also have same problems like Samsung.even though apple have release updates for I phone 4s.