nurnberg or berchtesgaden document center?

We actually did both this past May, and I hope you don't really have to choose, because both are very much worth visiting if your focus is WWII history. At Nuremberg, you can visit the Nazi Party Rally Grounds and the Palace of Justice. (The Old Town is also worth seeing, but your focus seems to be the documentation centers.) Both the Rally Grounds and Palace of Justice are easily reachable by tram and subway, respectively, from the main train station. You could spend many hours at both sites. The Palace of Justice was, to me, the most interesting of all, because its documentation center explains all facets of the Nuremburg Trials, which established the precedent for trying people for war crimes and 'crimes against humanity'. And, when you enter Courtroom 600 and imagine the 21 defendants sitting there (the courtroom has actually been re-arranged from how it was in 1946), you experience a deep sense of history -- and maybe a chill down your spine -- when you contemplate the evil that the defendants collectively represented. Also, if you watch Leni Riefenstahl's "Triumph of the Will" before you travel to Germany and then visit the Nazi Rally Grounds - and especially the Zeppelin Tribune -- you may once again feel a strange sensation when you stand on the very spot where Hitler viewed several hundred thousand supporters/soldiers, and then think about all of the death, destruction, and suffering that eventually was brought forth upon the world by these monsters. Berchtesgaden's documentation center (with underground Bunker tour), combined with a visit to the Eagle's Nest, are also very much worth seeing from a historical perspective. In fact, your teens might "enjoy" (probably the wrong word, considering the occupants) the Berchtesgaden/Eagle's Nest tour more than Nuremberg because of the spectacular bus ride up the mountain to the documentation center, followed by another bus and 400-foot (?) elevator ride to the Kelsteinhaus (Eagle's Nest). From documentaries and photos, the views of the Bavarian Alps are spectacular -- however, it was snowing the day we went (May 25!) and we couldn't see a thing due to the heavy cloud cover.

Any one else have any opinions???

My question would be, what does the rest of your trip look like? How much of a diversion is one over the other in the overall flow of your trip? What are you other interests, so that perhaps, for example, if you like hiking and you don't have any other Alpine destinations on your list, you could combine a trip to Kehlsteinhaus with a mountain excursion?

I've only seen the center in Nurnberg, but I've visited the town of Berchtesgaden. I'd take the Alps over a city anyday, although I do like Nurnberg.