I think I found something about changing mac address on Mavericks. The "sudo ifconfig en1 ether 4e:53:50:4f:4f:46" indeed does not take effect, even if it shows:
$ ifconfig en1
en1: flags=8963<UP,BROADCAST,SMART,RUNNING,PROMISC,SIMPLEX,MULTICAST> mtu 1500
ether 4e:53:50:4f:4f:46...