Sony Ericsson W300i Walkman

The Sony Ericsson W300i is the lowest model in the Walkman phone line, but that doesn't mean it is in any way the least capable. The device can play MP3 files and has a built in FM Radio tuner that uses the supplied in-ear headphones as an antenna; which receives surprisingly clear signal. The sound quality of the phone is sub-standard when using as a traditional phone, but when you plug in the supplied in-ear headphones with microphone and you have a rich stereo experience not only when listening to music, but when playing games on the built in JAVA platform, or even while making a call. The built in BlueTooth has more features than you would expect from an entry level media-phone. When connecting to the test laptop (13" Intel MacBook) the phone showed up not only as a phone, but also as a controller and I was able to use the numeric keypad on the phone as an secondary pointing device. I could move the mouse cursor, click and double click using the up-down-left-right and action keys surprisingly naturally - a feature not needed for a phone like the W300i, but a serendipitous addition that I played with way more than thought I would.
The negative aspects of the phone is the lack of the ability to sync to a PC. Even though it will communicate with and mount on a computer as a phone, it will not sync the contacts, calendar or bookmarks. Something that all phones that can communicate with a computer should do is at least sync the contact list with either Outlook on Windows or Address Book on a Mac. It may mean more programming before phones are released, but honestly now! With the line between computer and phone being as blurry as it is, all phones should have some avenue of syncing their contact list with the user's computer.
Over all a very nice Walkman, an adequate phone, a fun pointing device, but an unintelligent Phone-PC interface.

T-Mobile SDA

I purchased a T-mobile SDA because I really enjoy the Windows Mobile operating system and I prefer a T9 keypad over a qwerty keyboard. I am no speed texter, but I can type most words without looking using the numeric keypad. The SDA is generally the same size as most other candy-bar style phones, but slightly thicker.
The SDA is equipped with a mini-SD card reader but is located behind the battery, so hot-swapping is not even a possibility.
The battery gives an adequate life with having to charge every other night after average usage.
The phone is internet capable with the built in Internet Explorer, but limited to edge dial-up speed, which is enough to check e-mail or check your myspace and sometimes stream internet radio stations. But not enough to watch videos without taking a few minutes to download. The slow internet speed is offset by the built in 802.11b WiFi.
Windows Media Player Mobile is my favorite mobile music playing interface of all that I have used. It is not the most straight forward, but the ability to enqueue a selection of songs, remove selections and play radio streams overwhelms the slightly unintuitive placement of certain functions.
The phone has built in bluetooth and was able to see every device I threw at it; from head-sets to virtual keyboards, it connected and mounted them all. The only thing I was never able to communicate with was a wireless printer, but that was no surprise.
The signal strength is sufficient for normal use, but is underwhelming when compared to an average Nokia.
The tri-band functionality does not technically leave it classified as a "world phone" but I had no problem using it in both the United States and Canada. Since the Phone is a T-Mobile branded phone in the U.S. it will alway use T-Mobile service here, but in Canada it automatically connects to Rogers Wireless, which ended up being very convenient.
The SDA has a built in camera which works adequately, but can not ever seem to properly focus. It does, however record videos rather well.
All in all a great smart phone if you don't mind waiting for the internet, or if you are looking for a media-enabled phone but want a little more control over your playlist.