We've had UCS with the palo cards deployed with VMware ESX 4.0 for about nine months. In that experience, I'd say we've noticed the following characteristics:
1) The architecture forces the SAN administrator, the VMware administrator and the network engineer to workl together more closely than in our old environment which was VMware on standalone servers. It realigns teams within the technical support group.
2) So much is virtualized that there is enormous flexibility in this environment. Unfortunately, another way of describing a very flexible environment would be that the set of possible incorrect configurations becomes very large.
3) Solid technical information is hard to come by with the UCS. The cisco documention is still a work in progress and the universe of engineers with UCS experience is small.
4) The FI's are expensive enough that most shops don't have a test and development FI in place. So you find yourself reconfiguring on a production box, requiring a lot of juggling.
5) The hardware is fundamentally solid and trouble free.
