I've had the iPhone Second Generation for a week now and I thought I'd give you my impressions.
Physically the phone is nicer to hold and it feels better than the first generation. It sits better in the hand. Battery life is significantly less! Even without 3G, and with the brightness of the screen turned down, I get much less life than on my first iPhone. With the first phone I would easily travel for a couple of days without a charger - this phone can't do that. If you watch movies you may need to recharge the phone before the day is over. I will always carry a battery-powered charger, and the wall charger, when I travel with this phone.
Reception seems to be a bit better, but that is a hard thing to measure. Despite what it shows on the AT&T map I don't have any 3G service here at home, and I haven't been to New York yet so I can't tell you anything about the 3G speed increase. There is no question that the speaker, both the earpiece and the speakerphone, is louder and easier to understand. This is a real improvement.
The GPS is pretty useless right now. We'll need more software before it is worthwhile. The original iPhone dock doesn't fit - despite what they told me at the Apple store - so you should get a new one when you buy the phone. I was able to make my old one fit with a little shaving with my Dremel tool, so if you are handy you might be able to save the expense.
It's great to have a "normal" earphone jack, and all my phones fit it perfectly.
All the other changes are in software, which you can get on your original iPhone. Should you upgrade? I would say that unless you have a specific need, don't bother. There are not enough differences between the first and second generation to make an upgrade worthwhile for most people. If you do want to upgrade try to test out whether you get 3G in the areas where you want it. The AT&T map is not reliable in this regard. I, personally, am glad I upgraded, but I would suspect that most people will be happy just upgrading the software on their original phone.
Next installment, interesting apps that I've found.
If you have any questions about the iPhone send them to this alias and I will collect them and post the answers: [email protected]