AD / OD on leopard

I am considering using leopard server to just opull all the data from AD to the Mac Server for users and groups, my question is in Chapter 7 of the fantastic pdf Guide here (Page 34 section B) it talks of the client Authenticationg first to AD then to OD but is this just a hangover from before Leopard in the documentation, or is the AD login there for network access etc ??? since all account data will get taken from the OD login.. Also one question I have noticed the problem with KERBOS having to be disabled on the OD server in the Golden Triangle setup due to conflicts with AD and have seen this in a customers site, will this problem again rear it's head in the setup I want (Pure OD ). Thanks..