NQ brd = 3 song JSE harp and the all songs +2 Eminent flute or Forefront flute.
HQ brd = Carnwenhan, Gjallarhorn, Daurdabla
My example was comparison of NQ geo Dunna and Nepote Bell, geomancy +5, versus the idris geomancy +10. Compare this to Eminent flute +2 to Gjallarhorn +4. Because of the PERCENTAGE nature of geomancy spells idris geo sees much more boost than dunna geo, but the STATIC nature of brd the power isn't nearly as great.
their nq +5 on dunna is greater than the hq of gjallarhorn already. To be on a lvl field perhaps Eminent flute goes to +5 and Gjallarhorn to +10, but this is why I suggested that the buff be on Carnwenhan, else geo's would complain that brd's powerful instrument is so easy to get.
4th song does not apply to this example as there are only 3 ballads, this is comparison of ballad power.
Duration is long yes but this is about the power, and the power of songs comes from Gjallarhorn. Duration is a different story.
Yes duration will give more MP back for total time, but again this is about power of the buff not total MP recovered.
The main reason why brd isn't invited as much is because of the HP mechanics of alot of the fights. Because less people = less HP brd becomes a luxury to have. Also because of the time limits imposed by SE for these battles. Brd unless you SV is not about a sprint, by the nature of brd songs its about the marathon. Brd is helpful when a fight runs long as they are not bound by mp constraints and can provide the support needed for the longer battle, ie ballads.
The BEST reason for brd at the moment is Requiem 7. As a REM brd this is one of the longest dmging DOT spells at around 5 minutes unresisted. Very useful to keep mobs from regening in cases of wipe situation.