Either... maybe neither. GnR is a huge turn off to me as a theme-- I can't think of any potential band theme (that has any chance of actually getting made) that would be worse, other than maybe Rush. Zeppelin is just "meh". That said, sight unseen, I would probably choose GnR because I have absolutely no confidence in Stern for quality control or good code at release, and I don't have those concerns with JJP.