We did a pilot about 18 months ago and chose not to deploy for a variety of reasons. The technology has improved alot since them and the Intel Nehalem chips are driving up the density of VDI workstations/host server dramatically, so I'll be revisiting it again in a couple of months.
In a nutshell, here's what I walked away with regard to VMWare vs. Xen
- Both companies have good reference stories to tell. The products work, etc.
- VMWare and Citrix have different strengths
- VMWare single-instances memory objects and oversubscribes memory, so View will present Windows XP with 1GB (or whatever) of memory that may or may not be available. So you basically treat VMWare View VMs like regular workstations. (Sort of... you create a base image and then have linked clones with different apps installed)
- Citrix assigns small fixed memory spaces to VMs, typically 256MB. Then you use XenApp (formerly known as Citrix Presentation Server) to serve virtual apps to your virtual desktops. This works pretty well for many scenarios and gives you some really cool app provisioning capabilities.
- If you're doing VDI to provide consistent remote/in-office access, high-availablity desktops, and/or keep data in the datacenter, go for it. If you think you're saving lots of money by using thin clients, make sure you full understand all of your costs first.
- I think VMWare View has some features with alot of potential IMO, like the ability to "check out" a VM on your laptop and "check it back in" when you have network connectivity and the potential for vPro integration.
- VMWare has lots of really flashy/cool technology, but new features often require a new license down the road.
