The Mrs. and I just bought new phones. I picked up the Samsung Captivate (a Droid, closest thing to an Incredible you will find on AT&T) and she got the iPhone 4.
I’ve mostly been using mine, but have messed with her iPhone too, here is what I’ve noticed:
iPhone:
Pros -
[ul][li]It just works[/li]
[li]Better app selection right now[/li]
[li]Smaller phone, but still a nice sized screen[/li]
[li]Safari is great[/li][/ul]
Cons -
[ul][li]Limited customization options as far as display goes (I love some droid widgets!)[/li]
[li]The built in e-mail app doesn’t push Gmail for her. I haven’t spent time trying to fix this, but if you just do the default e-mail setup and tie in your Gmail account, it only updates when you open your inbox[/li][/ul]
Droid:
Pros -
[ul][li]Customization is huge, I like mixing widgets and app links so I can create my own desktops. One for sports, one for news/weather, one for work stuff, etc…[/li]
[li]Did I mention widgets?[/li]
[li]Notification toolbar, anytime something happens (e-mail, text, calendar appointment, etc…), it all shows up in one place that is on the top of all of your desktops, very nice setup[/li]
[li]Flash[/li][/ul]
Cons -
[ul][li]Default browser is good most of the time, but not as good as Safari (go in the store and load the full version of CNNSI.com for a good comparison).[/li]
[li]I’ve had a few forced app closings[/li]
[li]Battery life is awful under heavy usage. Probably won’t be a big issue once the newness wears off a bit and I’m not using it all day, but at this point it seems like a nightly recharge is a must[/li][/ul]
I went with the Droid because I knew it would motivate me to spend some time learning and writing Droid apps (no OSX for me, so I couldn’t do that with an iPhone). I think the biggest selling point for a Droid right now is customization, from the screen look/setup down to the open source OS, you can do pretty much anything you want. If you just want a phone with a lot of cool apps that just plain works, get an iPhone. If you want to customize it (either through apps/widgets or by writing code) then go with a Droid.
And I would not consider a BB right now unless you are looking for a phone exclusively used for work. They still do that very well, but there are too many extras on iPhones/Droids to pass up.