I just harvested a number of Saijo and Sheng from my mature trees; some of the Sheng were ripe and I was able to try them while the Saijo still need to be ripened off tree. So I have more to mention about the Sheng. My experience with this variety is that it has a track record as being as cold hardy as any kaki I know of, it's large with an interesting shape, loses astringency easily, it ripens well off tree and early season, it is quite sweet though not as sweet as some. Biggest drawbacks are that the tree is not as nice a landscape specimen as some varieties and the flavor is very light, similar to Hachiya. Saijo is a nicer looking tree - large and symmetric with many of the same qualities as Sheng but ripens smaller and slightly sweeter fruit a few weeks later.
Q