The Galaxy S3 has great battery life. People on here have shown that they have been getting a day or more per full charge! That's really great battery life. And as for performance, I was very impressed with the GS3's speed and response times. Plus it's lightweight, and very thin.
But I'm only concerned with battery life and a fully functioning phone.
I have 724 iOS apps, and still collect new ones on occasion. Most are free or freemium apps. I knew that I would have to buy exact duplicates of some of my existing apps I had on my iPhone. Oh well, not too much of a big deal for me.