I recently got a Sony Ericsson P1i phone and my review is based on my experience with it as compared to the Nokia E51 which I was using earlier. Considering the price point and the reviews, I was expecting this phone to be a fantastic device and I have been sorely dissapointed. I think some of the basic things that are required to make the phone user friendly are missing which makes the phone quite cumbersome. I am listing down a couple of the issues here
You can only search the names in the contacts in the order in which the name is entered. e.g. If I search for my name by putting Mitra, it will not find it in the contacts list unless I write Sumit. This is a bother with large address books and a feature which I much appreciated in the Nokia E51, where you could find all the names which matched the search you keyed in irrespective of whether it was in the first or last name.
There are no shortcut keys for essential items like bluetooth. The best you can do is define it in the standly icons menu. Even then, to turn the bluetooth on one has to open the bluetooth menu, then select a check box to turn the bluetooth on or off. Compare this with the Nokia E51 where you can turn the bluetooth on or off by just keeping the star key pressed. Other gripes include very little customisation possibility for the screens, no flexibility in defining shortcut buttons, a clumsy keypad which makes usability during driving impossible.
The Menus are also not intutitive unlike in Nokia and one has to spend loads of time before finding anything (e.g the Business Card scanner application is in the Office Section, although the icon shows a camera and people will logically look for it in the Media or Camera section) Also Sony Ericsson does not seem to have any matching applications for Nokia Maps & Sports Tracker. Despite being a nice looking phone, I am definitely going back to my Nokia E51. I think this is more a phone you show off with than really use.