Well, from what I have tried so far it really feels great!
The form factor is good but not quite as good as the Iphone, however, the Galaxy weighs less than the Iphone so that is a plus.
The screen is bright and clear and everything seems very smooth and responsive. All though I must admit that the onscreen keyboard takes some time to get used to, but I guess that is what you can expect when you are used to a normal phone.
I think it is too early for me to be talking about battery life since I have been playing around with this A LOT since I got it (downloading/installing a ton of apps and trying almost every single option that I can think of. : )
For more info I recommend that you take a look at this very nice unboxing video from Arne at
www.theunwired.net:
http://www.theunwired.net/?item=videoview-unboxing-the-samsung-galaxy-gt-i7500-android-smartphone