The Convoluted Lineage of Third Reich

One of the most famous wargames ever produced is Third Reich. The game was originally put out by Avalon Hill back in the '70s, and has gone through a series of permutations and expansions. I am not that familiar with any of the versions except the fourth edition, so I would love to know how the different variations compare.

Anyway, here is the basic lineage:

• Original game: Avalon Hill published four editions of the original game. I believe that there are substantial differences between first and second editions, but after that the changes are fairly minor in new editions; I could be wrong, though.
• Advanced Third Reich: As if the original weren't complex enough, AH published advanced rules in 1992.
• Empire of the Rising Sun: The rules were ported to the Pacific Theater in 1995. I've heard that this one has major problems, but I haven't played it myself, so that could be incorrect.

This is the end of the AH run of the game; AH went out of business a few years after Rising Sun came out. But the development of Third Reich kept going:

• John Prados' Third Reich: Originally published in 2001 by Avalanche Press, then updated a few years later, this one bears the name of the original designer, but I don't think John Prados actually had anything to do with this one. I believe that this one significantly changed the game, especially combat (from CRT to bucket-o-dice combat). The original version had some rather harsh reviews, and I don't know if the later updates fixed those.
• The Great Pacific War: In 2003, Avalanche ported the JP3R system to the Pacific Theater. I've read some pretty good reviews of this one, but I don't know how representative those reviews are.
• A World at War: GMT has published this monster, which combines the ETO and PTO. Its rule book clocks in at nearly 200 pages. My impression is that this version adheres much more closely to the Advanced Third Reich than the Avalanche Press branch of the family tree. Adam Starkweather wrote a rather scathing review of this one in Paper Wars #59, but it has a devoted following.
• Global War: According to Starkweather's review, the hardcore 3R gamers play their own, constantly evolving version of the game that they call Global War. It is based on A World at War, but with many rules tweaks since that game was published.

I'd love to hear from someone who knows these games about how the Avalanche Press and GMT branches of the Third Reich family compare. At the very least, I doubt we've heard the last of this line of games.