Ive heard both good and bad about Synchromesh. Good is, well, its good stuff. Cleans up shifts and whatnot. We used to use it a lot in customers cars. Bad, its not as sticky. Not something you can tell by touching it. Its like the molecular bond it makes with the gears and all isnt as sticky as some of the other stuff.
Redline shock proof is actually some really good stuff. Cost more, but is better all together. 2 quarts of lightweight and 1 quart of heavyweight. Its what John Shepard recommends to run in all his Shepard trannys.
But Ive personally never heard anything bad when using OEM Honda HMT fluid, in a Honda tranny at least.