Yes, MS Office 2011 for Mac is 100% compatible with Mavericks. I use Macbook Pro Retina and I too couldn't wait to upgrade to Mavericks due to the power-saving feature – AppNap, which inturn yields better battery life and performance too – since napping applications won't consume much CPU time.
Below is the screenshot (downsized to 50%) of Microsoft Word running on Mavericks. I did not face any issues as I worked with Word.
I also have a screenshot of Activity Monitor captured while Word was running in the background. You can see the AppNap status in that. I shall upload it shortly, as the number of uploads to Saval.in is currently limited, on hourly basis. I have also been using Microsoft Outlook on Mavericks for the last four days and I did not face even one issue. I have not spend much time on Excel and Powerpoint on Mavericks but, I have just launched the applications and did some user input, I did not find any issues there.
So, it is perfectly safe to upgrade to OS X 10.9, when it comes to MS Office. But wait, if you are using a corporate Macbook and if you were advised not to upgrade your Mac, you should wait.
Now that you have Mavericks 10.9.1, where Apple pushed all necessary fixes to the OS, you don't to have a second thought on Mavericks.
Mavericks is officially recommended to their techies in major IT corporates such as Google, Microsoft, Yahoo, Cisco, Amazon, eBay and Samsung.