Strange Headrat - im sure virtualbox opens SCSI VMware images (well, i have not changed many of the default VMware options and virtualbox opened up the VM just fine). It even loaded a VM configured to use two physical cpus, although obviously had a problem using them!
I quite like virtualbox - it does have a nice interface (much better than the horrible web interface of VMware Server 2), but having found that you can use the VIClient interface for VMware Server 2, im afraid i have not really found a reason to use VBox... When they get virtual SMP going, i'll definately look at it again.