Definitely, the ugliest thing I have seen in my whole life. You need sometime to get use to it, specially if you are going to use if just as a phone. To place a call you need to tap the screen at least 3 times and you have to look into the screen to do it so definitely this is not something that you want to do while you are driving. I'm probably too use to just hold pressed a key to dial a predefined number. Making a call using your voice is a "fantasy" included in that phone. At least for me. My Windows Mobile Phone was a lot better in this point.
Using the phone as a GPS navigation system in your car is far away... yet. You can get directions but nothing that you can use while driving. Again, my Windows Mobile Device performs better thanks to 3rd party software. But having a GPS I doubt that we are not going to see this applications ported to Android.
I could not find anyway to install applications unless they are included in the Market Place. And there are applications out there like Opera for Android that I wanted to test. I stayed away from the iPhone because I did not like the whole concept of a close market but so far I have not seen anything different on this T-Mobile phone.
A lot of potential so I'll keep it but I would say that this product was put prematurely into the market.
Update: I was able to install some applications out of the Android Market. Seems to me that to install the Apk has to be created using the latest Android SDK. I still investigating the issue.