The Red Hat VDI solution has come a long way … client-side rendering and media off-load, built right on top of the RHEV stack (no separate infrastructure!), user portal is part of the package (no additional purchase!).

Comparisons between VMWare View and XenDesktop show roughly functionality/feature parity, but Red Hat VDI appears *much* less expensive, and can provide both Windows and Linux virtual desktops.

http://www.redhat.com/summit/sessions/index.html#5

And checkout the Red Hat TCO/ROI comparison tool:

https://roianalyst.alinean.com/ent_02/AutoLogin.do?d=482903301639024770

However – a critical feature is still missing.  While Red Hat VDI looks like a great replacement for desktops, there is no iPad client yet.  For many, this may be the killer.  It is on the near-future roadmap though!