I understand your concerns about the additives in "blue," but I prefer the consistency, availability and price of Kingsford (especially the 700+ lbs that I got for less than $5/40 lbs recently). I would recommend doing a few cooks with the various brands you are looking at and weighing the results. I think they should all be fine in the PBC, but the Kingsford is recommended for the one reason I mentioned before (consistency). When it is recommended, it is because a smoker like the PBC is designed for a sort of one size fits all cooking method. I am sure you can find a method with any of them after enough trial and error.
In the interest of disclosure, I do not have a PBC. I do use a WSM 22.5" which is of course a fairly similar style of cooker.