Cisco Systems came late to the physical and virtual server rackets and that means it has to partner to get virtual server slices out there in the data center. And it thinks virtual desktop infrastructure, or what it now calls Virtual Experience Infrastructure or VXI for short, is the killer app for its "California" Unified …
XenApp is brilliant. Best on the market and streets ahead of the rivals. First choice for Apps.
XenServer is rubbish. Don't use it. Just, don't. While XenServer can run some VMs, it isn't Enterprise ready (yet).
As for Cisco reselling either - hmmmmmmm. Probably better to buy and develop a competitor if you want to try and find some advantage, otherwise you're simply following the technology. And HP, and Dell, and Fujitsu, etc, etc, etc