I came from an Apple 3G 8GB phone. I had put IOS4 on it, and it slowed my phone down so much the camera became near useless for me, cause it took over 15 seconds to load up (I have a toddler and need instant access to camera shots for the cute moments). I've never been an apple Fan, but when I got the 3G it was because it was a very cool phone that could do truly more then just make calls and text.
Apple Did some great things with the Iphone. They got AT&T to bend over and stop the previously rediculous data plan pricing on phones. They revolutionized the mobile gaming market, and the app store concept was a great movement.
My personal List of Pro/Con for each platform after owning my captivate since release.
Apple Iphone
+ Simple to Use UI
+ Simple Backup & Restore via Itunes
+ iPod + Itunes to Play, Sync & Rate Music
+ Phone Holds resell value
+ Ease of repair (I changed the glass on my 3g when I shattered it once)
+ Accessories like cases, car mounts & Bicycle mounts can be found for cheap.
+ Visual Voicemail is a plus and while not a big deal, its one I missed on my captivate until I migrated to Google VoiceMail.
- Heavily restricted UI. Themes are wonderful, and easy. Why apple doens't allow them is beyond me.
- Home button increasingly getting overused to band-aid the issue of lacking buttons.
- Multitasking is a hack.
- Premium Price for non-premium features. 8Gb/16GB/32GB pricing is ridiculous.
- Playback of nonstandard videos is very difficult and time consuming to convert to an approved format.
- Accessories have to be replaced (save cables) going to Iphone4 for any upgraders.
Android Specific
+ UI is easily customized, changed and easier to organize to your taste
+ Widgets for anything you can want. (Almost deserves two +)
+ Notification / Status Bar is implemented perfectly for one swipe access to all recent activity.
- Not easy to backup/Restore in comparison to iphone
- the UI can be overwhelming at first, and sometimes feels unpolished.
- Marketplace is lacking, and many apps feel unfinished
Captivate Specific
+ Screen is best screen I've ever seen on a phone.
+ Multitasking is super easy, and works very well on the captivate
+ Standard Cables (Micro-USB)
- USB slot is annoying to plug into sometimes
- GPS issues
- (until 2.2) mass updating apps on the device is a pain to deal with.
- Accessories like cases, and mounts are "universal" and never fit perfectly.
My wife has a 3GS running IOS4. Things she likes about my phone
+ The Screen is bigger and "crisper" to her.
+ The photoframe widget I have that cycles pictures on my main screen (lots of pictures of the little tike)
+ Woot.com and weather on one screen (or any combination of 2 "info" widgets in one place)
+ Camera takes better photos then her 3Gs
Other Misc details as a techie.
When you have a lot of notifications and updates on android, having them all in the notification/status bar, and hit the ONE you want to bring up is great, esp since it doesn't clear the rest off the bar. So when I goto a meeting, and ignore my phone for the duration, when I bring it back up, I can see a summary of all events that have happened (WordFeud tells me its my turn, 2 Emails, 2 txt msgs, and new conversations on gtalk). Had this happened on my iphone, I would have to manualy open each of those apps and have to remember to check each one individually. once you unlock your phone, your notifications are gone. Granted the apps like txt, and email will have the number of "unread" next to them, but there is no one stop notification place in iphone.
I give apple credit on the music front however. Playing music using the ipod is a great experience, and one android IMO can't come close to yet. Media scanning takes forever, and when I'm hiking/riding/driving using the music player it ALLWAYS stutters a little when a new song starts.
I love the google integration with android and being able to use google voice, and gtalk nativly. My wife had to buy BeeJiveIM to get close to the functionality I get for free with googletalk. Latitude is a lot of fun, and my good friends (NEVER COWORKERS!) have access too it. I don't know of a latitude equivalent on iphone, but its not a core feature that I would put as a plus or negative on either side. all iphone users are jealous of Swipe when I show that too them, as its a pretty neat ability. Plus its a snap to switch input keyboards on the fly in android, so when swipe is more annoying then useful, switching to android default is easy.
So All in All, for me Android on Samsung Captivate UnRooted/Unmodified, has more functionality and ease of use for my daily activities then my Iphone 3G did when it was jailbroken. Android, and android apps don't feel as "polished" as the iphone, but that doesn't take away any value of my android device over my experience with iphone 3G.