Is it better to write music in F♯ Major or in G♭ Major?

Question

Is it better to write music in F♯ Major or in G♭ Major? Seeing as they are enharmonic (in our 12-tone musical system), what are the advantages / disadvantages of writing in either, or should it be considered the same?

Factors / ideas to consider might be: circle of fifths, key signatures, enharmonic keys.

Answer 1

From a strict numerical standpoint, there's no difference: there are six sharps in F♯ major and six flats in G♭ major, so in this sense they are equivalent.

But there are some other musical factors you may consider:

• What is the instrumentation? Some instruments—like brass—are more comfortable in flat keys. Although players should be able to play in all keys, your brass players will make fewer mistakes in G♭ major, trust me :-)
• Similarly, what level are the players? High school brass ensembles could certainly play in G♭ major, but I don't know many high school directors that would feel comfortable giving their students a piece in F♯ major.
• If you have transposing instruments, you may find yourself choosing one key over the other to make the conductor's reading easier. A B♭ clarinet is written a major second higher than it sounds, so for ease of reading, you may choose to write everything in G♭ (otherwise your clarinet is written in G♯ major!). True, you can have flats and sharps in the same score, but again: if you can make the conductor's job easier, you might as well do it.
• What does the piece do harmonically? If it often uses, e.g., ♭VI (or even modulates there), it'd be easier to write it in F♯ so as to prevent any E♭♭ chords.

And so on.

Answer 2

for Keyboards and other instruments playing chords:

Keep in mind when the harmony goes across the circle of fifths (secondary dominants V7 of V7 of V7 of V7) in F♯ major it will turn from F♯ to A♯-D♯-G♯-C♯->F♯ and you'll need lots of double sharps. In this case I'd prefer to read in G♭.

While the relative keys are D♯ minor or E♭ minor, the dominant of E♭ minor is B♭7 and may be easier to read than A♯7.

So it depends - like Richard says - on the harmony and chord progression of the music which key might be preferred.