I've been testing out a Nexus One "superphone" for the past month and since the NDA is over I can finally share with you guys :^)
I was very skeptical about it being better than the iphone since using the previous G1 cellphone but now that i've had it I can say that I really enjoy using it. Is it an iphone killer? Well not really. It's more like a iphone equivalent but if you hate AT&T like I do then this phone is going to be a great alternative for you.
The 5mp camera is very basic and takes pretty good snap shots. The LED flash works pretty good although it tends to blow out highlights at close range. I did notice that video suffers from "rolling shutter". You see the "Jello Effect" when taking photos too but it's not too bad if you try to keep things steady before you snap away.
I also really liked using the GoogleSky feature where you point your "superphone" at any star and the app will tell you the name and position of all other stars and planets. Very cool! A great way to cheat when you take your honey bunny out for a romantic date under the stars and impress her with how much you know about the stars! Ha ha it worked for me :^)
The voice command thingy doesn't work very well but it's still cool when it does interpret what you say correctly. The barcode scanner is very useful too. Take a pic of any barcode and it will automatically look up the item and give you prices for that item if it's available.
The new AMOLED screen is fantastic! Nikon please put this in a high end camera NOW!

Google maps is great and updates relatively quickly when your scrolling around.
For such an old guy I love new technology! :^)