I've used Xen (current nVidia drivers don't support it), tried VMware (too klunky), and gave up on QEMU. I've been running VirtualBox for about 6 months now without any problems at all for those Windoze programs that I just have to and that won't run in Wine, such as my options trading software, VS.net, and Sparx Enterprise Architect (which is supposed to run on Wine, but has some irritating problems that keep me from being productive). The price (free as in beer) is right, and Sun is providing source if I really want to hack it (interested, but too much other stuff to do that pays me $$ for my time). So, my question is "Why bother with a non-free 2nd class VM?", or a non-free 1st class one (VMware) for that matter?