I don't see why not, I have seen a video of a tournament game where both players were using them. Not like its an unfair advantage...unless you consider "getting on with the game" an unfair advantage
I Chapter Master 454, Chapter Master of the Angels of Justice, Warboss of WAAAGH Gubskul, Commander of a Catachan Regiment, Phaeron of a Tomb World, Shas'O to a Cadre and Princeps of a lance of House Taranis hereby pledge that I will not take up any further models til all other prior have been fully built and painted to tabletop standards. There is no time limit for this task, there is no deadline. My oath is to solemnly complete the armies I have now, to see it that they can have their glory. Paint will be stripped from the old in need, thick may it be like ceramite I will see it removed so that plastic and metal alike may see light of new paint. Models yet to be, boxed and in darkness will be assembled with due care and attention. For this task I am permitted to still buy the supplies needed to do my task but not one model more.
http://www.bolterand...one-model-more/ the thread to my oath. My own reminder.
http://www.bolterand...rk-in-progress/ my own chapter
"The objective of playing a game is to win. The point of playing a game is to have fun. Never confuse the two"