I've just switch to the S4.
Positives:
+ 5" screen & video watching hands down over the iPhone/Touch
+ Look, feel, customizability of Android widgets hands down over iPhone/Touch
+ Air Features (ok... it's debatable
)
+ 13MP camera and HD video does a great job
+ Export iTunes Playlists to a 64GB SD card using simple sync software
Fails:
- Phone regularly and randomly drops and restores SD card (known issue)
- A SD card drop erases above Playlists (solutions = store playlist on device)
- Earphones quality < iPhone/Touch
- The built-in Video app crashes when using the folder view (downloaded another one)
Epic Fails:
- Android is obviously a close cousin of Windows: apps fail on a regular basis, info/settings disappear
- Car Bluetooth link drops every time phone goes to sleep seriously, its 2013!? (Who has a solution?)
- Could not register with Samsung as GT-I9505 does not exist in their list of devices
Bottom line:
* Android devices are nowhere near iPhone/Touch when it comes to stability
* If you are anal about your music and iTunes management of files, Android is NOT for you