I have used an Apple iPhone 4s, since they came out on day one... They are a reliable and solid phone BUT they are ridiculously over priced and Apple charges for absolutely ANYTHING.
People say that Microsoft are bad when it comes to money, and yet when dealing with them I was given free copies of Windows 7 after purchasing what appeared to be real (but was actually counterfeit) software.
Overall, the phone is well-built and will last, provided you treat it correct... If you 'have' to own an iPhone, then get one, but if you are just looking for 'any old smartphone' then perhaps look into HTC and Samsung, which are just as good but cheaper...
The lack of Bluetooth to other devices is also a major drawback, and so is the 'locked' software and customization... Overall if these two features were enabled to allow a complete customized look (if desired) and Bluetooth to ALL devices, not just other iPhones, then the 'features' would be a lot better...
Finally, like all smartphones, the battery life is not that great... It WILL need charging every night if you plan on making any real use of the phone... But that seems to be the standard for smartphones now... If you want great battery life, go get a Nokia from Big W... smartphones are not for you..
After a year of use on my iPhone, the battery has not declined at all in time for charge and discharge... It still lasts just as long.. (But as far as I am aware they have limited charge-cycles).