Last Friday, I stood in line for a few hours to pick up an iPhone 3G out in Durham.  I've had it a week now, and I figured I'd write up a short review comparing it to what it replaced - I'm afraid I don't have as much to say as Ben Nadel, so if you're looking for an in-depth iPhone 1.0 vs. iPhone 3G review, I'd check out his review.

First, some background:  for the past year and a half, I've been lugging around a Palm Treo 6-something.  About the only cool thing about it was that it was red, which continually made Adam Lehman jealous.  I'd picked it up because I was travelling a good deal more than I had been prior to its purchase, and I wanted a phone that'd let me do four things:

1. Sync my iCal
2. Sync my Address Book
3. Get e-mail
4. Instant Message (via GTalk or SMS)
   

When I bought it, I was assured that this phone handled all of it in spades, being even more compatible with my Mac than its Treo 7-series brethren, which ran some portable version of Windows.  It did perform all of the above, but with the following caveats:

1. An iCal event spanning multiple days would result in one event per day on my phone.  When it sync'd back up, it'd create all of these events in iCal.  Considering that I'd keep 90-day consulting engagements as events on a calendar, this made iCal syncing absolutely useless.
2. Address book sync'd fine.
3. E-mail....worked like 1 in 10 times.  Normally connections would just fail.
4. SMS worked great, but the IM software I used would crash randomly and reboot the phone.  I don't really blame the software, though, because of the largest problem I had with the Treo
   

At least once a day, I'd be doing something with the Treo, and it'd freeze then show me its boot screen.  About one in three of these times, it wouldn't even make it to reboot, and I'd have to remove / reinstall its battery.

Ok, now on the iPhone 3G side of the fence:

1. iCal just works.  It's their own software, kind of a no-brainer.  I'm impressed by the UI and by it automatically picking up alert settings.
2. Address book works, sometimes a little too well:  I changed the photo associated with the "Joe Rinehart" contact that I use to call home to a picture of my house.  It's also associated with the joe@firemoss.com e-mail account.  It unexpectedly reverse-synced the photo change to Address Book, so I now see my house whenever I read an e-mail I sent.  Works exactly as it should, but that's not something we're used to in the IT world (things working in the most logical and seamless manner).
3. E-mail works nicely.  I was out working from a coffee shop yesterday, my phone shook, and it was a grocery list arriving from my wife Dale.  I could zoom in and keep it legible while in the store.
4. SMS works great, giving an iChat-like interface.  I wish there was a mini iChat client on the thing, though, for GTalk - using Google's Safari based mobile app for the iPhone works, but it's not my favorite thing.

All in all, the iPhone has exceeded my expectations when it comes to business purposes.  Its wi-fi paired up great with the 4-5 local networks I use regularly, so if I'm not in a car and I'm in my hometown, I'm likely to be wi-fi.  3g is acceptable, but burns batteries - I've got it turned off unless I need IP connectivity and I'm not in a hotspot.  The UI, of course, blows away any phone I've ever used.  I'm a happy iPhone 3G customer.