I have been using Sony Ericsson P910i for about a year now.
Let me start with what I like about this cellphone :
Its a triband, so it works in most corners of the world. What use a smartphone if it can’t connect to network!
Excellent voice quality. Most of the time people cannot find the difference if I’m calling from a cellphone or landline. The call volume can be easily adjusted in the middle of the call using comfortably placed jog dial.
Easy to navigate. The interface is intuitive and easy to navigate. If you are previous Nokia user than it will take some time to get used to it. The phone before this I used it for 6 years, so it took me even more.
Excellent speaker phone. I have been on conference calls using this phone for over 2 hours at a stretch and had no issues except few interferences (which are quite common but not irritating).
The MP3 player is excellent. With 1 GB of expandable memory, it holds upto 100 songs with enough spare memory for applications and data. I use mp3 extensively on flights (has Flight mode so you won’t be asked to shut the phone off!)
1 megapixel camera is good too.
Excellent bluetooth. Pairs instantly with most bluetooth ear piece. I have paired with one from Logitech.
Won’t comment much on QWERTY key board. Its a matter of personal choice. I don’t use much of sms so I prefer touch pad which does the job well.
Good battery life. On some days I have used extensively i.e. about 5-6 hours and still has enough to go through the rest of the day. If you use bluetooth, has big screen, MP3, etc so I can’t complain that it drains out fast.
Decent internet connectivity.
Now, what I don’t like about this :
Limited availability of applications unlike for other mobile OSs like MS or Palm
Very cumbersome to download stuff from Sony Ericsson site like OS upgrades, ring tones, screensavers, etc. I haven’t tried from third party sites.
No connectivity to Lotus Notes email. Atleast I haven’t been able to figure out. This is a big let down for me. If any one was successful to get this connected to Lotus Notes than do let me know how.
PDF application is not generic one. PDF files from Adobe Acrobat lose formatting while using PDF application on the phone.
Let me know if you interested in knowing anything specific which I didn’t cover in the review.