No connectivity to the internet? -> use ULA, quick, easy, cheap.
ULA leaves a bad taste for a number of reasons, some of which have seen some discussion. What has not occured, and seems to be a major tenent of the ULA zelots, is how conflict resolution is to be done. if ULA is sufficent, in and of itself, then why do we need to have all the rest of the 128bits of space? if ULA users ever have a conflict (and yes, they will) how will the conflict be resolved? and then there is the nasty delusion of "Internet"... protestations to the contrary, the VSNL view of the "Internet" is vastly different than the US DOD view of the "Internet", is vastly different than the GE view, is different than the AS 701 view, is different than the Chinese R&E Network (CERN) view.... which one(s) count? Policy routing dictates that there is no such thing as a "global" routing table... For me, as long as I have IP reachability to those folks whom I want or need to talk to, I could care less about the "rest" of the folks using IP to move datagrams about ...
Greets, Jeroen