Okay here were my reasons...
1) The onscreen keyboard input system refused to register my keystrokes correctly just way too many times.
2) I can't SMS without looking at the keypad unlike a normal phone. Lack of a physical keypad is a pain.
3) The battery in the Iphone is non removable. If the battery dies, well u gotta ship the device back to Apple to have it fixed
4) For the price, it better provide 3G
5) No expandable storage... no SD card slot
6) It lasted me barely a day and half on full charge
7) Now this is the biggest reason to reject it outright... Its a smartphone which supposedly allows you to check e-mail and the damn thing doesnt support syncing with Microsoft Exchange.
8) You can't play wave files, nor can you set them as ring tones.
9) Forgot to mention earlier... it doesnt support any form of push technology for mail/calendar syncing. Not that useful to me but for some folks this is absolutely necessary.