we aren't leading the pack by any means, but am in the midst of moving from 6400's to Viprion and from V10 to V11 at the same time.
just completed my last configuration migration to the new boxes.. a dry run. think i got it down.
then decided to check through Devcentral to see what other tips might be around.
three HA pairs of 6400's going to a pair of Viprion occupying 3 guests.
a few snags, but for the most part it is going well. the bigger was that the Viprion chassis handles the interfaces and trunks so the guests don't need them. A few edits of the config files repaired that. then used that as a time to cleanup some of the names to make them consistent as well.