i have seen dead pixels on 3 S3 and on 2 S4 out of the 5 or six of each one purchased in my office, new from retail stores, and some online also new, most just had one but one s4 had 2 dead pixels and a red stuck one.
Mine is fine, didn't even know this was an issue which is surprising considering we have a phones 4u store in our department. I haven't heard any dead pixel issues.