I was using the iPhone through the weekend thinking that I would probably leave the Galaxy S3 hooked up to the TV indefinitely but I put the SIM back to the S3 on Sunday night.
1. Battery life on the iPhone 4S was terrible. Minor use and it went 100% to 80% in less than half an hour in just sending a few text messages, 1 10 minute phone call, posted 1 instagram photo, and read on twitter and facebook for a few minutes. I do the same routine on my S3 and I will have more than 95% battery. Battery was at 10% by 5PM when when I had the phone unplugged from charger at 9AM.
2. Got too used to the big screen on the Samsung. It's really difficult reading on the smaller screen. Simple physics, not much more to say
3. Galaxy takes better photos. One can argue this all day but people have noticed the change in quality on photos I post to Picasa, Facebook, and Instagram.
4. The Back Button. You will have no idea how useful this is until you truly experience Android. It may not seem like a big deal at first and I thought the same thing too but when I was using my iPhone, I was really missing it!
5. LTE - High speed speaks for itself. Hopefully this will be on the iPhone 5.
6. Google Music - Much better than the stupid Music Match and Google Music is free. If you haven't experienced it, then you have nothing to argue about.
What I Missed on the iPhone
1. iMessage / Facetime Integration with MacOS - This works really well for me. Love how everything integrates with other iOS devices as well as Mac OSX. Sure there are Android alternatives to texting on your desktop like Mighty Text but it isn't as refined as how iOS does it. If WhatsApp had a desktop application then I'd easily drop iMessage.
2. Shoot pictures using the volume button - the way the iphone is designed, it's shape makes it a perfect point and shoot sized camera.
3. Photos automatically upload to iPhoto and Aperture libraries through PhotoStream - sure there's Drop Box but with PhotoStream, I don't really have to think about it when I want to pull up photos from my Mac
4. Mail App. I hate the default Mail App on the Galaxy S3 (for exchange mail). So much smoother on the iPhone and the Corporate Directory is very well integrated.
5. Most car audio systems including my headunit has better support for the iPhone especially for Pandora and other Music players. I can use Bluetooth on Android but sound quality through the cable is much better.
I think what I'll do is have my Samsung be the weekday driver since battery life and reading emails on a larger screen is more importnt to me. Both phones are equaly fast and work smoothly but the S3 has LTE which I really enjoy using.
On the weekend, when I don't have to really on battery life as much (calling clients, my employees, sales team, etc) I can use my iPhone while I have the S3 hooked up to the TV to play videogames