I gotta say this is fantastic. This is the kind of thing that we can wave at big N and say "HEY, look what we can do!!!" major props to the GuitarFun team.
I do have a few things that came up as issues however:
-The sync, its slightly off yes, but the songs I tried weren't really noticeable, I only noticed because I was expecting it after reading this thread.
-(using the wii-gh3 guitar) there is no method of pausing, to either change settings, restart the song, quit the song, etc.
-The Refresh Songs menu item does not actually work. I loaded the game with 7 songs on an sd, played them all, then took the card out, erased the 7, added 3 and put the card back in. pressed Refresh Songs, and it starts to give an error. the program has to be quit (back to HBC) then re-launched for the songs to be read from the card.
-I would also suggest adding a Gameplay Options menu wherein there would be settings that can be changed for Screen lag, Grace period for hitting notes, as well as grace period for HOs/POs
-Most of the time that I hit a chord (usualy did this on 2 note chords) I would receive credit for 1 of the notes, but not both, then it would register the second one as a different strum, and I then lose the streak, points, and music.
-When playing, say blue with a rapid altering between blue and green, if I wanted to hold green and blue and strum to hit blue, it should work....thats classic guitar hero functionality, that is not the case. It registers that as a chord being played and acts acordingly (not hitting the blue note).
Also, i like the "3 note special" function. Especially because that implements the same functionality that my ACE program does ACE thread reading the Expert chart and deriving the easier charts from that.