Transmission fluid

I know there are other threads on this but most seem to be quite old and there is always new stuff coming out and people with varying opinions.

Just some info about my trans, I've got a 5speed with 310k km or 192k miles on it. Got the car last year and have 0 clue when the trans fluid was changed last. I get a grind going into 3rd at the top of the rev range and it won't let me into first when moving at slower speeds (too slow for second but not a stop).

I've heard some people say to stick with OEM Honda and other people claim Amsoil synchromesh gets rid of all of their problems. I'd love to hear if you guys have good experiences with one over another or a whole different fluid I might not know of.