I've got the exact same marking on my waterblock and sk-7 as the one SSS posted. it isn't "scorch mark". It IS oxidation (and also slight "molding" of the copper... I can read my cpu specs in the marking.) The ones in the article look different so i can't comment on those however.
I am now, and have always been using AS3 on both. I've never even seen a tube of PCM+ unless my eyes brushed over it in compusa or something.
About the material drying out, almost any nonsilicon based thermal paste will, and silicon based ones will eventually seperate. That is why most long term uses have PCM (as in the sort on the bottom of retail heatsinks) on them.
I'm not sure what is so scandalous about these articles, except that pcm+ is marketed to long-term users whereas AS3 really isn't (to my knowledge).
The thing that really caught my eye were the results of how severely pcm+ whalloped as3... I thought they were just about even. Even more important to me is how severly AS5 whalloped pcm+. I doubt I'll be buying pcm+ anytime soon... but I'll get as5 as soon as I can (if it isn't outrageously overpriced) and compair as3 and as5.