Another few things to note. The spread of CPU load for people who have 4-8 cores is significantly better. It is well distributed now.
One of my personal favorites is that the system overload messages have disappeared when hitting play the first time on a track. That always pissed me off. Even with 1 track of a solo violin it would crash and system overload the first time hitting play. That doesn't happen now.
Most people are claiming that they don't even experience system overload messages at all anymore. It has only been a few days but some of us have been purposely trying to reproduce the problems logic 8 had. So far it has been wonderful. Sure it has some bugs to be worked out and probably more when Snow Leopard comes out, but for now it is running better then 8 did. Unless of course you were one of the users that never used any of the features in Logic 8 that had a bug.
*Additional note - getting lots of positive feedback that 9 is curing sluggish plug-in responses (such as gui loading times etc). However there are some plug-ins that are not working with it at the moment.
Maestro2be