Writing this review after using the phone for nearly 1.5 years.
My Need: Ive only had smartphones. First was a Motorola A768i, which was a good phone in its own right for its time, and a Nokia 5500 when I lost the Moto. The 5500 was a disappointment despite my low expectations. And when it started dying, I picked up this 2 month old iPhone 3GS on eBay when a friend was coming back from US. My primary need was data as I had figured I could avoid opening the laptop just to reply to mails or quickly look up something. Had also used a first gen iPod touch for a few days when it came out and was pretty impressed by UI.
Cost: Buying a used phone saved me quite some money, although there was a risk of the phone being defective, was in luck as phone was as good as new and flawless. So the Rs.17.5K I paid at time of purchase was pretty reasonable to start with, and is looking better as days go by. It is impossible to calculate the peace of mind that comes with phone, will explain that below.
Experience: Have found most people who talk of iPhone are those who dont own it. A couple of months after using the phone, I forgot all about phone and was pretty delighted with the apps that make this gadget much more capable and useful. I use my phone to keep track of my accounts. Helped me track and streamline my expenditure and save more money for investments. Wunderlist for iphone is real good and helps me note down those many many small tasks that are often forgotten till something gives away or somebody complains. Mail, twitter, tumblr and Linkedin are mostly handled from phone as are quick visits to web, specially when Im out or in middle of something. All other smartphones can do all of the above, but iphone makes it painless. Cousins Android phone home screen has "Task Killer" that he says he often uses to kill apps that are silently running in the background and draining battery, something that is handled automatically by OS on iPhone. It is this and other such small things that make this phone such a pleasure to use. After a few months, the phone becomes second nature and gets pulled often for this and that, becoming more indispensable as days go by.
Performance: Its not very fast by todays standards. But its very usable. Network speeds are not all that great even with 3G and broadband in India, and the phone is most of the times waiting for data, which is the case even if one buys a brand new hydra quad, multi giga memory super smart phone. Stability of the phone is top notch. App crashes are rare events, and needing to reboot the phone is even more rare. Touchscreen response is fantastic. Zooming in and out of webpages is slick as is scrolling. Heavy formatted pages do tend to jerk when zooming or scrolling, but I dont know if newer phones are better at handling this. Display is brilliant, colors are perfect as is intensity of backlight. Larger screens in other phones look good, but are difficult to use with a single hand.
Camera: is good with colors, but performs well only in uniformly well lit environments. Shots in dark often turn out grainy and details visible to naked eye is sometimes lost by the camera. Nevertheless, was shocked by its quality for macro level photos. Had to do with my iphone once on a client visit to take some pics of a damaged part. The resulting photos looked as if they had been composed and shot by a professional. Still, if you are a mobile photography freak, you may be better off with newer iPhones.
Overall: Frankly, the iphone is in a class of its own despite what pundits and geek review sites etc may say. One and a half years after I started using this phone, Ive simply grown to love it more everyday . Cant say the same of for my two previous phones. Some people may miss out features like blue-tooth file transfer or Fm radio. Guess it depends on what you really want out of your phone. For me, this phone has meant lesser use of a computer and also many more things that are only feasible with a good smart phone in pocket. If you are a geek or nerd who loves exploring limits of your phone and its features(I was a geek once), stay away. As should people who only need a phone with a camera and music player.
If you are looking for a device that is more handy than your laptop or netbook, smarter than a phone and quick access to Internet, mail or other network centric activities is useful to you, then seriously consider an iPhone(any). If you are on a budget, give 3GS a serious look.