I currently have an Android phone, but I got a lot of exposure to the new iPhone 4 quite recently because of a large project building a multi-platform app for one of my clients.  And now I know what I've been missing!

So here's my thoughts on how they stack up when you try to use either of them as a real-world, heavy-lifting, core-part-of-your-daily-business-life tool.  My Android device is a Motorola Droid; the iPhone is a new 4 model.

AS A PHONE:

Android: poor reception, poor voice quality.  Will not pair with the Parrot Bluetooth in my FJ Cruiser (but this is a known problem with this Motorola phone, not Android in general).  Pretty nice integration with Contacts, except when you want to search your contacts to find someone's phone number, you can't rotate to landscape mode to type the person's name.  BIG DUMB MISTAKE.

iPhone: slightly stronger reception, better voice quality.

SYNC TO OUTLOOK:

Android wants Gmail to be the center of your universe, and everything is supposed to go through that. 

Both devices will sync your calendar and contacts with Outlook; neither will sync your tasks or notes without a third-party app.  For my Droid, I use CompanionLink USB software, which generally works well, except it puts some of my recurring appointments off by 4 hours, and about every 3rd time, syncing Contacts takes 20 to 30 minutes to complete (I have about 2500 contacts in Outlook, so not a crazy number).

BROWSER:

Both are pretty good.  iPhone won't do Flash sites though.  Both have troubles with sites with complex Javascript in the UI.  The Android browser has a neat Bookmarks page that takes a little thumbnail of each of the web pages you've bookmarked.  Well, it'd be neat if it worked--about 1/4 of the time, it associates the wrong thumbnail with the bookmark.

EMAIL:

iPhone works well; in the app we created, we easily created HTML emails from within the app and were able to send those out to the wide world without any real issues.  Creating HTML emails within Android seems much more difficult (in fact, we haven't solved that yet).  Android can RECEIVE HTML emails however.

Android's split email into two apps:  GMail, and everything else.  The GMail app is slow, buggy, impossible to figure out, and I still don't know how to refresh my inbox.  I keep navigating between folders and refresh and eventually magically things show up.  The "everything else" email app is much more straightforward to use, but it's very buggy.  If you're opening an HTML email with images, and click the Show Images button, then delete the email before it's done, it moves to the next email in your inbox, shows that subject, sender, etc.....and the images and text from the deleted email.  :-(.  Somehow the inbox gets 1 to 5 empty emails every day:  no subject, no sender, no content.   When you forward emails with attachments, well, you can't.  Never mind.  You can delete emails, after which they go into the trash.  Don't do this by mistake, because while you can go into your Trash folder and look at them, you can't un-delete them, you can't forward them, you can't reply, etc.   Oh, and you can't empty your trash...I'm now over 6,000 emails languishing there.  Speed is an issue as well--plain text emails open quickly, but emails with images can take several minutes to open (and no, it's not the image size...little 5k company logos are enough to send it into a tizzy).

CAMERA: 

iPhone camera is really, really nice....super picture quality.  Much better than the Android, but admittedly, that's more the Motorola Droid's problem rather than Android the OS.

The Android's video camera works really quite well however, surprisingly better than the still camera!

The photo gallery works really well on iPhone. Android 2.1 had a much clunkier looking gallery, but it worked well, and it was fast.  Android 2.2 has tried to "dress up" to work more like an Apple product, with fade-in/zoom-in to pics, etc.  But it's very, very VERY slow.  If I have a photo in my phone's built-in RAM (not even the SD card) and I pop open the gallery, to show the first photo takes so long that my phone usually powers off the display first.  The menu pops up at the bottom (after I power the display back on), and then immediately changes its menu options (what????).

WIFI:

Well, it works on the iPhone, and it doesn't on the Android.  This also is a Motorola problem however, and if you call the Verizon tech folks, they get all quiet and spout some line about Motorola supports the wifi and it's not their problem and do I have any OTHER questions.

STABILITY:

I've not seen any crashes on the iPhone.  Apple's App Store is pretty tough on app makers in terms of testing their product before allowing it to go live on iTunes App Store, and it shows.

The Android's most important app (and no, it doesn't come with it) is Advanced Task Killer.  It allows you to stop an application that's running and not behaving/hogging memory/draining the battery (which doesn't last long--I can't go a full day just on standby on 1 battery, let alone if I use it to call people).

The email app locks up pretty regularly, and has to be killed.  I probably run Advanced Task Killer 10-20 times a day; most days, I'll have to pull the battery out as well, as things get all balled up somehow and it's beyond Task Killer's abilities.  This seems especially true if Maps is running.

APPS:

Yes, the Apple App Store has a gajillion apps available, but in reality, for anything you want, need, get the giggles over....there's an app for that in BOTH the App Store and Android Market.  In fact, even for obscure tasks, there's generally a big selection of apps.

I will say that the Android Google Maps/navigation integration is really quite nice.  It's nearly as good as a real Garmin, except for one important feature:  Garmins tell you what your NEXT turn is, whereas when using the Google Maps navigation, you'll make a turn, then wait 10 or 15 seconds for it to tell you where to turn next.  Whoops, it was BACK THERE.  

SPEED:

This was the most startling difference to me when I started working with an iPhone--it's SO MUCH FASTER.  I will say that when my phone was running Android 2.1, it seemed much faster than after the "upgrade" to 2.2.  But still, not in the league of the iPhone.  Perhaps with a newer Droid phone it'd be better.  When I got mine, I first got an HTC Eris, which was miles slower than this Motorola Droid, and I decided after a day or two I couldn't live with the speed, so spent the extra $ to switch to the Motorola.

SUMMARY:

The Android is going to be a pretty nice alternative, once it's ready for release.  Yes, it's released now...but it's not ready.  It needs massive speed improvements, a lot of bug-fixing for the basic, included apps.

Now that I've actually used the iPhone, I've lost my anti-Apple attitude entirely, and am very glad that Verizon now has iPhones in their stable.