Reliable good performing Windows phone

I have had this phone for almost a year and overall I am very impressed.
The phone has stood up to a lot of abuse and drops, and still works like a champ. Synching with Outlook on Windows Vista is superior to any non-Windows phone.
I also set it up to use DirectPush email delivery from Exchange Server. This is a feature that is similar to Blackbery but works with directly with your exchange server to notify your phone when email arrives. I have found this feature on average uses about 9 to 11 MB per month, so make sure you get the unlimited data plan.
3G internet connections are truly impressive. By using the phone for an internet connection and linking it to my laptop via BlueTooth, I was able to browse the internet on my laptop from anywhere I had a phone signal. Which worked out great on my motorcycle trips.
Call quality is on par with the best phones and I have not had a problem with signal strength. Bluetooth is well integrated and allows multiple connections simultaneously.
My only gripe was for an interesting anomaly with the bluetooth integration with my vehicle. I have a 2007 BMW, and with several other phones I own and tested, the bluetooth connection not only allows incoming and outgoing calls, but also downloads your contact list (address book) to the car so you can look up a person from the radio system. With the Samsung Blackjack, everything works for dialing and receiving calls, dialing using the radio keypad and so on. The only feature that does not work is downloading my address book to the car.
The included extra battery is a great addition, and is needed when you are using 3G internet. If you want to save battery life, you'll have to turn off 3G (there are a couple of web-guides out there to create a toggle button to turn 3G on/off).
This is also a quad-band GSM phone which makes it perfect for traveling. I have personally used it several countries in Western Europe and the Middle East.
AT&T has not released an update to Windows Mobile 6 yet, which I will report on as soon as it's available.
1/28/2008: Good news, WM6 update is now officially available from Samsung web site. The update brings several enhancements, speeds up tasks, allows Word/Excel document editing and viewing Powerpoint. And it has solved my bluetooth compatibility with the car. The update is not the easiest to implement, but step-by-step directions from the web site make it approachable. The WM6 update can't be installed from a Vista PC, so you make sure you have access to a Windows XP machine.