Samsung Captivate running Android 4.4.4
iPhone 4 running iOS 7.1.2
When I first bought my Samsung Captivate, the iPhone was the "dominant" consumer mobile platform. I was turned off to it mostly for two reasons, having to use iTunes for the bulk of my media requirements at the time and the screen size. Over the past few months, I've had the necessity to use an iPhone 4 due to a hardware crash on my HTC One. I went this way rather than using my old Captivate mostly because I didn't want to have to get a SIM card that fit the Captivate. With the backstory complete, I figured I'd provide a summary of where I stand on the platform I prefer and the ups and downs I face on each. This review will be short as I don't do too much so I'll get the easy question out of the way. I am comparing these two particular devices because they have comparable hardware and the version of their OS is the latest that is currently running on each. The Samsung Captivate is running CyanogenMod 11 with Android 4.4.4. The iPhone 4 is running iOS 7.1.2.
My first main concern is battery life on each device. Each lasts about 7-9 hours with regular use (emails, SMS, podcasts, Facebook, and Feedly for the most part). The main difference is that I find the iPhone has better active performance and steady battery usage while Android has better idle performance and average active battery usage. At the end of the day, I'd give my vote to iOS as I had a higher battery percentage on the iPhone but did require active monitoring of what I used. On Android, I didn't have to think about usage as much but does require not using battery heavy apps when not needed or if I know I won't be near a charger for a while.
My second concern is UI interaction. I give my vote hands down to Android for two main reason. The first is the use of the back button and easier app switching. I found the back button an invaluable tool to go to any prior screen mostly because the back arrow is near my thumb. Having to reach to the top of the iPhone screen (while smaller so easier to reach) did not work for me, especially since menu options are usually nearby. App switching is the next point of contention as I could not consistently have the app switcher open on the iPhone. Also, this ties directly to my use of the back button as often times I would want to go to my last app via the back arrow but having to use only the home button didn't work as it goes back to being unable to consistently open the recent apps drawer.
The final 2 points of difference that is more of a personal issue relates to usage. The first is app organization. Having to go into settings to only find out apps cannot be organized by name doesn't seem very user friendly as it takes longer to find apps or setup the main screen to put apps into folders takes time out of using the device and getting to where I need to go quickly. On a related note, having to see app icons for items I almost never use is quite the hassle as it becomes necessary to create a folder to "hide" these icons from view. I give this particular element to Android as having a homescreen for most used apps and widgets then an app drawer for all apps seems more user friendly as not everyone uses the apps the same way so when setting up one's homescreen, why not have a place to have it truly customized. The other main point of contention is the warning that Cellular Data is disabled. My main gripe is that if one goes through the trouble of disabling access to an app's connection to use cellular data, a warning does not need to pop-up everytime it checks for a connection to mobile data. For me, I know I turned it off so I don't need to be reminded I turned it off.
In short, I still give my vote to go Android but if no customizing or settings changes are desired, then the iPhone may be the way to go. While I find the UI on Android to work better and be more user friendly, the iPhone works well if the user doesn't want to change or move things around and wants a device that will use minimal apps. Android does work as well out of the box as the iPhone but works better for those who care about how their device operates, even at a minimal level, to have a truely personalized device.
*I did not bring up battery life and screen resoultion for modern devices as I believe Android and iOS devices are on par with each other and is a matter of the differences noted above, which in retrospect, does not seem to have changed much in the past couple of years.