I've been on this site for years and I know 9.9/10 any response not in favor of Apple will be looked at negatively or within the last year or so get the down vote.
That said, I've been using iPhones from the original 4GB model in 2007 through the 4S since launch up until a week ago or so when I got the S3.
That said, I am enjoying my S3 a lot more than I enjoyed any iPhone. Why?
In a nutshell android is more open. iOS talks about being PC and it has come a long way. However, when I want to add or remove content it's a lot more straight forward with the S3 and typically can be done on the device.
With iOS I usually have to get on my main computer or remote login to it for simple tasks.
I also have found myself printing a lot more pictures in the last few days by just being able to go into a store and pop my card from the phone in.
Apple works great with other apple products, android so far is working great with everything.
I don't see one better than the other. iOS and Android can both be great in their own ways.
At first, the S3 was just going to be my toy until the next iPhone came out. Honestly, I'm not sure if I'm going to switch back to iOS anymore.
One thing I will say though is I feel if I drop my S3, it's going to break into 8 billion pieces. iPhone build quality is definitely better.