I've bought and sold my 3gs now but feel obliged to share my experience with it.
Lets start with the good bits.
-The iphone has just about everything you could want on it. Apps are widely available and there's an app for just about anything.
-The iphone is very user friendly; it's easy to work even if you are a technophobe.
-The touchscreen is superb, even if you have fairly chubby fingers like myself.
The iphone is great at what it does but this is where the main problem lies.
Because the iphone is loaded with apps, a camera etc. the battery life is shockingly bad, even if you just have it switched on and don't use it, you will be lucky to get 16 hours standby time, that figure is critically reduced if you browse the web or call out. If you use your mobile alot for texting and calling you wont get more than 5 hours out of the iphone and you cant just stick a new battery in because its built in. What you are left with is a mobile phone that isn't mobile because you have to charge it twice a day this kinda defeats the point of having a MOBILE phone.
Overall the iphone is a fantastic phone but is fundamentally bad as the battery life is simply unacceptable, if you want a mobile phone for calling, texting and browsing web I recommend you buy samsung's galaxy s (just like iphone but better battery life and faster), if you want a cool gadget that does just about everything, buy an Ipad. In all honesty, the Iphone is a bit pointless you would be better off buying a different phone and an Ipad. Battery life is the only real downside to this phone but its such a big issue that it can't be ignored. Also the ringtones are annoying lol.
My rating: 68% (Would have been in the 90s if it weren't for the atrocious battery life)
Reliability: 9/10 (just don't go too far from mains electricity)