The latest release of the iPhone software has been out for a couple of weeks now. As I mentioned before, I didn't jump to an iPhone 3G, so I'm just running the v2 software on my v1 iPhone. Now that I've been living with it for a couple of weeks, I'm mostly happy with it.
This is probably just me, but the single thing that I've wanted the most is Exchange on my iPhone. The App Store is a nice-to-have, but not essential. (In fact, as of this very second, I can't get any app downloaded from the App Store to launch, so I'm in the middle of restoring my iPhone to see if that will fix it. Restoring takes forever!) I've been dying to have Exchange push to my phone. Push email isn't the killer app for me, it's push calendar invites. I kept my iPhone synced pretty well, but there's always an updated calendar invite at the last minute — someoone cancels, changes rooms, whatever. Not having push calendar meant that I was never 100% certain that I was looking at the latest and greatest (especially since the latest and greatest could be less than five minutes old).
Having push email has meant that I've had to make some changes to my usage. Push email is a great way to run through a battery charge if you get a lot of email. But the push only works for your inbox, not for your complete folder structure. This is actually a pretty big benefit in terms of battery life. I've always been a big user of rules, but I had to go in and make sure that I was using server-side rules so that only things that I really care about end up in my inbox on my iPhone.
I have a few annoyances with my Exchange mail on my iPhone.
Calendar is mostly unchanged from v1, it's simply adding push to it. Which means that my complaints about the calendar are still here:
Now that I'm in Exchange push, I've noticed a few additional issues with Exchange calendar invites:
Contacts support is good but not great. I've got a big address book (1000+ contacts), and there's an obvious performance lag when scrolling through them. I've also noticed that my iPhone doesn't update my contacts when only the notes section has been changed. I use notes extensively in my contacts, so this is quite disappointing.
I had really hoped that the new version of the iPhone software would bring us tasks and notes. But no, that's just a pipe dream. The notes app on the iPhone is entirely useless to me without sync. I've currently got more than 50 notes in Entourage, ranging from the Caltrain shuttle schedule to a vague stab at my research schedule for the rest of the year. Likewise, with a complete lack of task support at all, let alone task sync, I'm on my own. There are third-party apps that try to fill this need, but none of them quite meet my needs.
In all, I'm still quite happy with my iPhone. I think it has some major shortcomings as an enterprise device, but I'm hopeful that they'll get fixed.
You should look at SMEScheduler for the iPhone for scheduling (www.thesmespace.com/SMEScheduler) - it handles group scheduling with voting and best of all final meeting requests are automated and come with Outlook and Ical attachments (as well as Google Mail) - also supports timezones and real time meeting alerts with Twitter - I use it all the time for meeting up with other mums during the day.
Would a 3G iPhone be better for me? No, I don't think so.
Apple has a ways to go before they can match the ActiveSync functionality built into Windows Mobile. Most of your issues are addressed in Windows Mobile.
That said; I am sure Apple will keep adding functionality and since they have control of the update process (unlike Windows Mobile), we won't be waiting years for fixes...