As one would expect, the quality of third party prducts for D&D varies, more than the quality of the WotC products does. But some stuff can be exceptionally good, e.g. ENsiders Zeitgeist adventure path, or it can simply be useful for a specific situation, like I hope the Out of the Box product is. Besides quality, prices also vary in a wide range, and not necessarily correlated with quality. Of course in the case of the Beadle&Grimm’s stuff, the adventure itself is a WotC product, and you pay extra for additional materials like maps and handouts, not for the writing of the adventure.

One problem with getting additional materials is the addition of shipping costs. I pledged $20 for the pdf only version of Out of the Box. The $50 pledge of the hardcover version adds another $24 for shipping to Belgium, and the $115 pledge with maps and tokens costs $70 to ship. As much as I love D&D battle maps, I think I’ll make my own in this case.