Galaxy S3 now or wait for the new AT&T Androids...?

I'm currently using a (terribly condition) iPhone 4. To be honest, I am extremely bored of iOS. It just feels so stale compared to Android and WP8. I am eligible for an upgrade with AT&T and I'm a bit confused as to what to do. Here are my options:

  1. Trade my iPhone for an Atrix 2 and wait for the HTC One X+ (or for the S3 to get cheaper)
  2. Get the S3 for $139.99 on Amazon and sell my iPhone for $160
  3. Keep the iPhone

Sorry if this is a stupid question, I just want some outside opinions. Thanks!