I have had the Iphone 4 for about a year now and have some great apps, have a screen protector and tough cool cammo rubber protector ... no issues so far , use it daily for texting, calls , web, gps ... all works well. My wife has the same and daughter has BB.
BTW best thing with the Iphone 4 is Facetime , its very convenient to video call with relatives and see my nieces and nephews that are far away.