Positive:
I can not see myself using any other phone after I have got iPhone. It simply outclassed all other mobile phones in the market. I am an avid internet user and if you are one iPhone is the thing. Unbelievable browsing experience which you can only dream of having in Nokia Phone(My previous phone was Nokia 9300). iPod is inbuilt so music is done. Camera quality superb. Have never seen 2 mp camera giving such a cool output. Inbuilt email works just fine. I am never away from the internet as have also taken vodafone mobile connect service which is 3 times faster than GPRS but still very slow for download. Plus all the cool sites have iPhone version now like facebook, digg, rememberthemilk etc.
Not so positive:
I have unlocked my iPhone(too bad but could not resist) so I am not able to upgrade the software may be that is why it crashes more often now a days. I miss sms forward feature but there are 3rd party applications to do that. Bluetooth does not work with other phones. Many features are missing right now but in upgrades we will get all those features dont worry, you can trust steve jobs and apple for that:)