You will get some burn-in with AMOLED after a few years no matter what. Pentile AMOLED (in the S1 and S3) is also superior to the AMOLED+ in the S2 for longevity, or so says Samsung.
My 2-year old Captivate has some up top where the notification bar is, and on the bottom where the keyboard is, and where the high-contrast black&white WordFeud game tiles are that I always play.
The burn-in ghosting isn't THAT noticeable, though, unless you're viewing mostly white images or webpages.
phone #1: SGS3 (SGH-i747); ROM: CM10.1 Nightly (JB 4.2.2); kernel: Stock @ 1.5GHz || KT747 @ 2.1GHz(!); misc: Incipio Silicrylic case; 64GB class10 microSDXC
phone #2: SGS1 Captivate (SGH-i897 r1008); ROM: CM10.1 M3 (JB 4.2.2); kernel: Stock @ 1.0GHz; misc: $0.99 silicone case; 32GB Lexar microSDHC