Not sure yet if this is good or bad, but Innotek, the developer brains behind VirtualBox, just announced that Sun Microsystems is purchasing them. I'm betting its a GOOD thing. I've been a _very_ happy user of VirtualBox for over a year now. I use it on Ubuntu. I've found that it has outperformed VMWare Server/Player/Workstation in most of my observations. In the press release, Sun's intentions are that VirtualBox will continue to be aimed at the developer workstation.
Sun already has [recently] entered the server virtualization market with their xVM product. xVM is aimed at server virtualization and I'd bet good money it isn't cheap.
I'm anxious to find out how Sun will market VirtualBox to additional developers.
Things I like about VirtualBox --
1) User experience. Fast. I have no issues with Virtual Box's performance. I recall the last time I rebuilt my virtual machine, I was able to re-install WinXP in about 30 minutes. Seems that for VMWare Workstation 5.5, it always took 2 hours.
2) Shared folders. Fast. Easy. VMWare drives me nuts -- there is a 10 second pause the first time you access a shared folder. That 10 seconds doesn't seem like a lot, but I always catch myself thinking -- "What is faster? Copy to a USB disk or shared folders?" VirtualBox is fast and without delay.
3) Stability. I've had a few BSOD using VirtualBox, but is that because of Windoze or VirtualBox? I'll never know.
4) Free. VMWare has Server and Player versions which are free, but, especially in the case of Player, they are very stripped down. VirtualBox is free. Please keep it that way, Sun.
Anyways, I surely appreciate the developers at Innotek. They've done a fantastic job and I hope Sun treats them well!