http://www.illuminatelabs.com/products/beast Lightmass and Beast are two separate things, Lightmass is our solution, Beast is an integrated partner, similar to speed tree, scaleform, and others (link). go to town guys!!
at the very least its nice to have an updated version of the tools. After using beast on AO2, going back to the old way of doing lighting at home was kinda lame-o, lightmass should be similar and just as wicked from what i hear.