For all those O&G players out there, you will be using the NEWEST edition - it is getting released in March.
Lists should be built around that book - not a weird hybrid!
I know for some this might seem like a blow to your ability to get a fully painted army up in time for the tournament, with the edition of new models and alterations to current units. I'm afraid thats just the way it goes, but the painting scores do take such changes into consideration (i.e. sudden changes in lists, late additions to lists).