is there a document somewhere with a brief explanation between the differences and benefits of layer 2 / layer 3 and kernel or userland ??

im sure a layer 2 kernel mod is the most efficient, yet, is there a test or comparision and explantion of why or what benefits ?

im just doing a comparitive between my current mesh running bmxd in userland and say batman-adv kernel mod, and id prefer to document the data and reasons in the internal wiki for our information, helps not only myself but others understand why :)