Virtualbox - simply because I've used nothing else yet.

vmware

No doubt.. Virtual BOx

VirtualBox for 2010. I suspect I will answer differently for 2011 picks.

Same here, haven't tried other VMs but VirtualBox. For me, it just works™.

VMware - they are the 900lb Gorilla in the Enterprise Market. Which is better than MS

You will only know what type of people are reading this forum, rather than knowing what people really use. I can see that there's really not a lot of people vouching for Xen, simply because that's not the type of product you will use on the desktop. Yet, Xen is used by the vast majority of providers. In fact, even Virtuozzo has more users, but it's not in the poll because it's just a jail, not a full virtualization env.

So, like many polls on the internet, we shouldn't care too much about the result, but care about people's comments more.

Personally, as a web host, we use extensively Xen (we have nearly 100 servers running it). It's a wonderful product which is rock solid. But the goal is really different from the one you will have running Virtualbox or VMWare. It's really server oriented, and it doesn't really have a good desktop interface.

On the desktop side, I think that Virtualbox is a winner. If you have the chance to have VT support on your computer, and if you run an NVidia board with decent OpenGL support, then running an emulated Windows will be extra fast, even when using 3D (virtualbox translates D3D calls into OpenGL). Also, the GUI is really simple and everyone should be able to use it.

Now, as for KVM, it's a product which is already going to be dead. Yes, it's better than Xen on the desktop, but Virtualbox is more easy to use. No, it's not a replacement for Xen on the server side, because it doesn't have the needed features (like PV, mounting a *partition* and not a full HDD, and so on).

There was a big big buzz about RedHat dropping support for Xen in the favor of KVM. But at the end, this was only silly marketing from silly people. No, RedHat isn't Linux. And if everyone was saying that KVM was in Linux and not Xen, since 2.6.37, this is wrong. In fact, this has always been wrong: Xen has always been slowly up-streaming to kernel.org. Now, in a couple of Linux releases, we'll see the back-end drivers for Xen being upstream too, and we will be able to say that Xen is fully supported. Now, everybody will wonder: how exactly RedHat will advertize about not willing to support Xen anymore, when it's included in the upstream kernel? What will be the stupid reason they will push? That it's too hard to package the userland tools as a RPM, when it's already provided by xen.org? This makes no sense anymore, and they already look really stupid commercials marketing-oriented press-release that have zero understanding on the underlying technical involvements.

At the end of the day, everyone should be extremely happy that there's both KVM and Xen out there, and that they are COMPETING products. Overall, this is improving things, especially when one considers that Linus is only accepting one patch for one needed feature: at the end of the day, we got best of both worlds inside kernels from kernel.org.

Thomas

Thomasgplhost -

Thank you for some very interesting - and insightful - comments.

Sincerely .. PSM

VirtualBox is not the most versatile, yet it's easy to use.

Virtualbox. Seems much faster than KVM (for Windows at least)

I like VMware Workstation. It is amazing and easy to use.

Have any one used stackVM ?

I'm using Xen. :P

Would Proxmox fit into this category? I had problems choosing between KVM and OpenVZ when I voted, because I use both under the Proxmox umbrella.
Just thinking out loud...

Proxmox doesn't appear to be a Virtualization Product in and of itself, it simply implements other Virtualization products, so would not be eligible for this category.

--jeremy