Take a look at the blog post Cisco: Just Like Any Other Office Communications Server ISV? for some official words (finally) from Microsoft on Cisco’s CUCiMOC and Microsoft Office Communications Server integration.
He hits the nail on the many questions I have raised at customers, including the supportability problems in terms of integration at the desktop level with program version dependencies and especially the (lost) user experience when using CUCiMOC. Furthermore Currently Cisco is setting a Version 8.0 / Q3 CY10 date for supporting Windows 7 (And also with limited support for 64 bit).
Furthermore (as he also notes) it is important to note the dependencies and lost features (RDP Sharing, Audio/Video/Webconferencing etc – that you would need to buy from Cisco).