Why I'm still using VMware
As I've mentioned before, in theory I should hate VMware because it involves more or less binary kernel modules and I've usually avoided that sort of thing like the plague. These days Linux has plenty of virtualization alternatives, ranging from somewhat more open to genuinely open source. Yet I still keep using VMware.
The short answer is that for me it remains the best of a bad lot of choices. Everything else is some combination of less convenient to interact with, more obnoxious (yes, I'm talking about VirtualBox and Oracle), or has more impact on my system configuration.
(I'm also not sure of the state of snapshotting and rolling back virtual disks, which is something that I use fairly frequently in VMware.)
There is no nice way to put this, so I'll put it plainly: convenience matters to me a lot and all of the open source software I've looked at is simply significantly less polished and directly usable than VMware is. Creating and adjusting VMs is easy in VMware's GUI and I'm especially happy with how well VMware handles VM (graphical) consoles. Everyone else seems to use VNC (or lately SPICE, which I have no experience with), but my interactions with VNC-based VM consoles have not been exactly inspiring. I'm especially dubious about using VNC for Windows guest consoles for various reasons.
(Yes, I prefer to interact with virtualization through a GUI. It's faster for what I do, partly because I can rapidly and directly select what VM I want to do something to, plus if I'm going to work with a VM's console I need a graphical window for it anyways.)
In theory I might be able to drive my primary Ubuntu test VM entirely from the command line and interact with it over SSH, but that's only one of my VMs. I'd like to have a system with both good command line support and a good GUI plus virtual console, but if I have to pick only one of those two I'm going to pick the latter.
By the way, I'm aware that my desires here are basically irrelevant to the open source virtualization people. In a way I agree with them in that they're almost certainly making what are the right technical choices in terms of how virtualization works, how virtualized networks fit into Linux, how VM consoles should interact with the rest of the system, and so on. I just don't care and I'm being selfish; I want the convenience that incestuous hackery delivers.
Sidebar: the two big features VMware is missing for me
The two features I would really like in VMware are an option to zero a
host guest disk (which would just delete and recreate the
underlying files) and an option to boot a VM into the 'choose a boot
device' BIOS menu. Since a VMware VM only has a very narrow window in
which you can activate that boot device menu (perhaps a second or two at
most), the lack of the latter is especially irritating.