I am using e90 after using the 9300i. Its fast but lacks many important basic features like view miss number when you miss a call and check the list, the user might be on your phone book but if you want to call him from your land line. You want to view the number, you do not have this important feature.
Delay sending of messages: In 9300i you have the feature of sending the message at a particular time and date.[GOOD FOR BIRTHDAYS]. This feature is not available in E90
Auto Focus: If you want to take an instant picture, its not possible as the camera tries to get the best shot and you lose the shot
Battery: There is a gap of 2 mm between the battery and the phone and this leads to loose contact and phone freezes and you have to reboot. Not worth the money
Keyboard: Compared to 9300i the keyboard is not good. Nokia should try to update e90 software