Which software do you think is the best for VM/VPS/VE/VDS hosting.

I can only speak as a customer, but so far I've had the best luck with Virtuozzo. I signed up for a VPS from zone.net last week for some testing, and so far the performance has been great. This is for a Linux box, not Windows.

I'm also eager to try out a decent Xen vps, but the price is always at least 25% more than a comparably spec'ed Virtuozzo VPS. It's just not in my budget right now, but hopefully will be soon.

Types:
Virtuozzo is a commercial virtualization software which includes a GUI control panel.
OpenVZ is a GPL'd version of Virtuozzo (no GUI control panel).
Xen is GPL'd virtualization software (no GUI control panel)

Control Panels:
HyperVM is a control panel for either OpenVZ or Xen software.
GPLHost is a GPL'd control panel for the Xen software.

In my opinion, Xen is the better virtualization software as it seems to use the fewest resources. As for control panels Virtuozzo is the better of the the control panels.

It really depends on what you are looking for out of the product and what it will be used for.

As an example, Xen allows you to use different kernels on a per VPS level if you wish.

OpenVZ is pretty close to Virtuozzo as they are related, the pluses to Virtuozzo are the templating system and the control panel which I have not found any equal to.

The downside to Virtuozzo, it isn't cheap, but we expect it will pay for itself...

-Robert

We use Virtuozzo and OpenVZ with HyperVM.

I have expirimented with Xen before and we do use it for internal use but not yet on production machines.

We've used OpenVZ, Xen and VMWare.

Xen and VMWare are complete virtualization machines, but suffer in performance quickly. VMWare is expensive and Xen is time consuming to work with.

OpenVZ is extemely fast but is somewhat limited by swap and kernel modules.

So it depends what you want to do. There is no one perfect solution for everyone.

For web hosting internet servers I'd recommend OpenVZ.

I hate to disagree with you here.

Xen will provide you 100% guaranteed access to the resources that are provided to your VPS. Meaning, you will ALWAYs have your 1GB of ram, regardless of what other VPSes are on the node itself.

OpenVZ and Virtuozzo on the contrary, excel at doing the so called "burst" which means, using a POOL of resources and spreading it between VPS's in a node. You can also limit the use per VPS in OpenVZ, but not quite as Xen.

OpenVZ and Xen use different virtualization approaches: OpenVZ uses OS level virtualization, while Xen uses paravirtualization. This is a pretty significant difference and proponents of each will argue it to their advantage. OpenVZ folks will say their approach allows for better resource usage and density. We feel paravirtualization provides good resource usage and superb isolation. Translation: your neighbor can’t bring the whole box down.

Xen also requires fixed memory and disk definitions, OpenVZ allows for burstable memory usage. That is the biggest difference you will see, burstable memory rates on Virtuozzo offerings, whereas Xen has hard, fixed caps. Burstable memory is great if you have control over all of the virtual servers (everyone is friendly), but when you have a diverse environment like ours, we prefer hard memory caps (you get what you pay for).

I have used VPS software. OpenVZ is the one I like best of all.

i've been use xen and openvz

xen sometimes running slowly if your ram not much for vps.

openvz run more quickly than xen

I am going to have to recommend HyperVM we use it in our datacenter and we are very happy with the results.