Well, I stood in line for an hour yesterday and got my 16MB iPhone 3G. I must say (and I hadn't used the previous iPhone) that I am pretty impressed by this device. The 3G really works well and so does the WiFi.

Couple of points:
1. Love the way that I can have apps on the phone. I know that it's not just a 3G feature. I had multiple Palm (and Visor) devices over the years and there were hundreds of apps for those. Most of the apps are still very much first-gen and there are some that are missing.
2. The WiFi connection to my home network is stronger than my ThinkPad and my Palm Tungsten C. It can connect from rooms that those devices can't.
3. It's a slick device. It will replace my Motorola RAZR + iPod (for commuting) + Palm Tungsten C + laptop (for short trips) and it means that I can check email and websites anywhere that I can get a WiFi, 3G or cell-phone signal.
4 GPS feature is really convenient. It's not going to replace X5 or the Nuvi 660, but it's good for giving directions. It's especially useful that a lot of apps can use GPS (with your permission) to customize the info for where you are e.g. weather, news.
5. Calls are sharper than any other cell-phone that I've used before. I don't know if this is the 3G network or the iPhone technology or both.
6. Negative is that the keyboard entry is going to take some time. I have been "spoilt" by the BlackBerry and Palm Tungsten C so I'm getting lots of errors entering letters. I'm not big on texting, so it's not too big a deal; I'm more an email kinda guy and will continue to do that from my PC's.
7. Another negative is only 16GB memory! I'm going to fill that up in no time and will have to spend time managing what I load on it.