After upgrading to Mountain Lion, my boot and shutdown time is longer than before upgrade. I upgraded my macbook from 10.6.8 to Mountain Lion with app store download. My Macbook has 4 GB Ram and 2.4 GHz processor.
MacBook, OS X Mountain Lion (10.8.2)
First look at your login items, ensuring that they run with Mountain Lion or are at least the current version. Same thing in the System Preferences window, look at the bottom for any software listed, and ensure each runs with OS X 10.8, or is at least the most current version.
You can install an SSD (solid state drive) in place of your hard drive. That will dramatically speed up your boot up speeds.
In startup items there is only itunes helper and I hide it. In system preferences there are flash player, growl and perian. But I have no idea about growl.
How can I fast my boot and shutdown time?
