Open source vs proprietary
I tend to look at things this way. There are three criteria I look for in a solution:
→ It works
→ It's supported upstream
→ It's open-source
I'm mostly happy with 2 out of 3. So if there's something that's proprietary, I'll be okay with it so long as it works and there's support for it.
Case in point, at a lot of customer sites, we use VMWare Server 2 to run VMs atop a Windows host. Last place we used it, it was a 32-bit version of Windows Server 2003. It worked well, and only got replaced because they needed to allocate more than two CPU cores to a VM. At the moment, they run VMWare Player, which mostly works, except it won't start as a service.
At another site, I tried to get it going on a 64-bit Windows 2008R2 box. Ubuntu would start to boot off the ISO image, but would hard-lock when it started booting the kernel. My hand-crafted VM did similar. Quick investigation revealed VMWare Server was no longer supported, so out it went, and in went VirtualBox and VBoxVMService. That has been happily running the VMs for months now at this new site (a defence base).
Had VMWare Server been still supported, I might've considered installing a newer version and/or chasing up a fix, and continuing to use it. No support, and no source, means I can't fix it, and they won't fix it. Open source, I at least have a hope, and I generally will contribute things back, even if upstream isn't that interested.
This, my friends, is what separates the likes of Pedro from a freetard. Not just something being free, but something we can adapt, improve and give back to in a meaningful way. :-)