This night I tuned in on the weekly VMware Podcast: http://www.talkshoe.com/tc/19367. Had some good info, and even better Q & A's.

Keypoints:

17 load balancing options for etherchannel
Nexus runs NX-OS, very similar to IOS but not 100% the same
The VEM can be installed using VUM on each ESX host
The VSM can be installed on the cluster, a second VSM will use the first VSM settings, no additional config needed
Network Access Control is supported
Upgrade NX-OS is the same like physical switches
Great security stuff

This is just a tip of the iceberg :-). Check out the above talkshoe link and listen to the podcast. I can't wait to install the VSM/VEM and license ad try out on my ESX4 boxes.