Thanks for the profile tip. That got things to work quick and easy.
Only noticed 3 things so far: Silverlight, Icons and Speed.
Silverlight: 5.1.20513.0 is loaded, and seems to work on one of the aforementioned test pages (with the bubbles), but the Microsoft page does not think I have a compatible browser. They have a note on that page that ONLY IE supports 64-bit versions of Silverlight. It will not even let me download an x64 bit version.
Icons: Other odd problem, when I first ran Waterfox, and it created a new, empty profile, the browser buttons did not render properly. The minimize, maximize and exit buttons on the upper right corner of the window were all invisible. Mousing over showed an orange/reddish glow behind the window, but the button never appeared. Maybe related to not finding the profile? After I specified the location manually, and changed IsRelative from 1 to 0, everything else seems to work fine: Flash, Java, all my addons.
Speed: Upon first loading up (I have about 290 tabs open, I was in middle of testing something else), it loaded very slowly. Slower than official 32-bit build of Firefox. Subsequent loads are a little faster to prompt for master password, but are equally slow to open the main window after. 15-20 seconds.
Anyways thanks again Mr. Alex. I look forward to the official release.