I had an 06 MacBook that was an absolute lemon. Had to bring it in for randomly turning off and go through two motherboard replacements before they sent it away for 4 weeks to redesign the motherboard. Then it still had to go back in several times before they finally just gave me a new one almost a year newer because of how troublesome it was. I don't think this is a sign of getting worse!

(I now have a 2012 rMBP and absolutely love it)