If you make a Time Machine backup before you install Yosemite, it is really easy to roll back the installation. Make the Time Machine backup and then load up Yosemite. Note the time of the time machine backup. Then, if the browser does not work, simply press and hold Command+R when you start the computer to enter recovery mode, and tell it to restore from the time machine backup you made earlier. Whala, everything will be back to normal after that.
I'm still not sure it's wise to load beta software on a mission critical computer, but only you know what your schedule is like, and what risks you can afford to take.