I always thought that VMWare Server is a great piece of software. It is a fast and convenient way to run my soothsayer builds on a Windows platform without actually having to get dirty running it on my (real) hardware.
However, it has a couple of shortcomings that I can no longer live with:
- it is not free as in freedom (although it is free as in beer)
- it does not work with the latest kernels (its kernel modules do not build with the latest kernel sources)
QEMU is a great option when you need to emulate different architectures. I've used it successfully to build soothsayer for the ARM architecture, for example.
QEMU is both a machine emulator and a virtualizer. It is very fast when used in conjunction with the QEMU accelerator (KQEMU kernel module). However, it has a few rough edges. In particular, setting up networking for the guest machine requires a bit more work than someone accustomed to VMWare would expect.
VirtualBox, on the other hand, gives pretty much the same user experience as VMWare. VirtualBox OSE (which stands for Open Source Edition) comes with a captivating graphical user interface, similar to VMWare's. Creating and running virtual machines is just as easy as VMWare, and everything works out of the box.
VirtualBox's performance is not as good as VMWare's, but it is good enough for my needs and it does save me the trouble of having to reboot into Windows for real.
Give VirtualBox a swirl if you've never tried it.