Switched from iPhone to S4 about a Month Ago: My Impressions:

Seeing as how there are a lot of threads on here about switching/pros/cons/etc. about these phones, I figured that I would share my experiences so far having had both of them.

First, overall, I like the S4 MUCH better, so I will speak from that perspective.

Pros:
- Screen size. Awesome. This can not be overstated. I have large hands and the iPhone 5C and 5S is like a friggin wet bar of soap. The screen is worth the purchase alone.
- Customization all across the board. This is a big deal.
- Widgets are awesome
- Battery life is better
- Notifications, for the most part, are better. Not necessarily in the design and usage, but in the execution as it relates to the device and battery life.
- Seems like S-Voice understands my redneck arse better than Siri.

Cons:
- Camera isn't on the level of Apple, but I rarely use it, so I don't really care.
- The "back" button is in the bottom right hand corner. I'm left handed, it's mildly inconvenient, but that's nitpicking.
- Visual Voicemail isn't as good as Apple's, unless there's an app that's better that I just haven't found.
- The default text app is fine, but Apple's is better.
- Need a better email app. There's nothing "wrong" with the S4's, I just prefer the Apple version
- The default keyboard. After years of typing on the Apple, this keyboard screws me up. I switched to the google keyboard and all is right with the world.
- I actually kind of like the design and application of iOS Navigation better than GMAPs. GMAPs is worlds better on the actual accuracy of the maps, though. Just personal design preference.

Most of the cons are probably a result of the switch. IE, if I had started on Android, it wouldn't be an issue at all. It's more of a learning curve. Hell, there are probably even some apps out there to address my concern, I just haven't looked hard enough.

If I didn't mention something, it's because I feel that the phones are equal or I don't use that option.