Caveat emptor
Avoid the pain we've had with multicast on the Nexus 6001, release 7.0.0.N1.1, by not upgrading.
NX-OS v7 brings to the table some really nice features, but to let multicast slip through the net is absolutely incredible by Cisco.
Mutlicast doesn't work between different vlans if the receiver joins the group before the sender.
Confirmed bug