In general, Under Heaven is a lucious stroll through an almost China replete with spectacular character building. The key exception is Wen Zhou, who in the latter stages of the book seemed too much like a villain charicature undeserving of the role he played. This is my second time reading Under Heaven and I once again found myself weeping uncontrollably when reading about the death of Wen Jian at the culmination of the main storyline.
I agree with the others that suggest that Under Heaven could be a trilogy of books by itself. GGK does a better job than many of interweaving multiple story-lines and several main characters into a single whole for 90% of the book. The ending of the various stories was a bit anticlimatic
with the post-scripts providing the fate of the main characters.