I'd like to point out something that every vet and AD knows. Performance reports are crap. You have to be more than just a screw up to get a bad one, you have to be on your commander's shit list. Even then it's no garauntee that you'll get a poor one. Hell, I got an article 15 and a demotion in rank once and still got a great (though not perfect this time) PR, and the written recommendation was friggin' glowing.
That written part is the important thing in reading into the PR. You look for how it's written and what is written. There are words and phrases that sound like glowing praise but are stock phrases used on almost everyone's PR whether they're good at what they do or not. Then there are the ones that sound more personal and are due to your immediate supervisor and chain of command actually giving you Kudos.