I had the same problem, installed Mavericks on Mid 2012 Macbook Pro and my machine slowed down horribly, also my battery was showing much less time than normal... I did a recovery and reinstalled Mavericks again and everything is running perfectly... just had to re-authorize some of my programs, otherwise all seems perfect so far!
the following is taken from this page: http://www.apple.com/osx/recovery/
Just hold down Command-R during startup and OS X Recovery springs into action. It lets you choose from common utilities: You can run Disk Utility to check or repair your hard drive, erase your hard drive and reinstall a fresh copy of OS X, or restore your Mac from a Time Machine backup. You can even use Safari to get help from Apple Support online. And if OS X Recovery encounters problems, it will automatically connect to Apple over the Internet.
Hope other find this works for them too! Good luck!
I am having multiple issues after upgrading as well, first Finder kept crashing every few seconds, hereafter multiple small issues. Most of them could be solved by upgrading 3rd party applications.
In order to find the culprits of your slowdowns, open up the Mac OS X Console and keep an eye on the messages that keep popping up during use. The the printed strings often have the name of the app or you can do a quick online search.
This way I was able to find several 3rd party utilities which were causing problems and updating or disabling them made my Mac feel a lot faster.