Yep, I had a reason to break out my old MBP and install the newest version of OS X on it. It works wonderfully for a five year old box (the SSD sure helps!), except for not being able to sleep properly. What worked for me was disabling "safe sleep" a la this hint.
sudo pmset -a hibernatemode 0 sudo nvram "use-nvramrc?"=falseThen restart. You can also remove /private/var/vm/sleepimage to save some space, which is nice.