The three-row diatonic in G/C/F has turned out to be an amazingly versatile box. This one has three voices and three registers to change the combinations of voices. With the low voice engaged, the low notes of the G row are growly, bassy, profound. With only the two middle voices engaged (slight tremolo, almost "dry"), those same notes are expressive and have quality that reminds me of a human voice; the high notes of the C and F rows become flutes and piccolos!I initially considered the G/C/F to be a G/C box with an added F row, but because of the bass arrangement, it is more like a C/F box with the added G row, if the comparison to two-row boxes makes sense at all. To learn tunes typically played on G/C, in which a pulled F bass/chord figures importantly, I need to either learn the tune on the C/F rows, or learn the tune in G/C, utilizing the F row and crossing all three rows on the press to hit the F bass/chord.
The major advantage is that there are "reversals" of many notes, allowing the player to choose the bellows direction (and thus, the bass/chord) for most runs of notes in the central keys in which the box is played. There are also reversals for several of the bass/chord combinations, especially when the thirds in the chords are not sounding.
The most crucial disadvantage is that there is a steep learning curve for using the "accidentals" buttons -- the buttons with G#, C# etc. (these are the buttons closest to the chin on each row).
The size of this box has not proven to be as much of a problem as one would be led to believe by some of the predominant "wisdom" that has been posted on the internet. I primarily play one-row, Quebecois-style melodeon, and I am able to play everything from my one-row repertoire on this box. It doesn't sound the same, of course, because it is tuned in a very different way, and lacks the piccolo reeds that the Mélodie has, but the weight of the box is not an issue in relation to speed.
The only time when I wish it was lighter or smaller is when I'm transporting 2 or 3 different boxes to a rehearsal or gig!
