I haven't upgraded to 9 yet due to the fact that my HP855C printer driver is not compatible with it. A co-worker has installed it and says it seems to run smoother and has not caused any problems not listed on the compatibility notes on the net.
He did say that it seems to have eliminated the 20-30 sec. mimi-freezes that were present when using Road Runner and 8.6 system. I still have them but have decided to keep them rather than lose my printer.
Go to: http://www.macintouch.com/m90_compatibility.html
This list the known problems and software fixes for those that have them.
