The good things added in this VirtualBox are USB support(OSE doesn't have that) and added built-in support for more OSes. However, it's not without a small annoyance or two. In the previous VirtualBox, once I set up a virtual machine to run in Fullscreen mode, it stayed that way until either I shut the machine down or directly chose to take it out of fullscreen. In this new VirtualBox, it kept going back to windowed mode several times while a machine was booting up. Certainly not a showstopper, but quite annoying. And performance overall seemed pretty much the same, even after I tried enabling some options for Intel virtualization optimizers.

But all in all, not bad for Sun's first release after acquiring it. I give it four stars, and the fifth one will come once they fix that annoying fullscreen-to-window bug.