same ilvl - monk or dragoon

[GunsBlazing]

And a little bit more versatile too. They can Buff Physical DPS and Reduce Damage taken (5%) every 90s

I wouldn't say Machinist is more versatile.

Machinist can, as you said, buff physical DPS a bit and reduce the damage the party takes.

Bard, in turn, can buff magical DPS and also reduce the enemy's evasion by 10% with a 100% uptime. Rain of Death is critical if you have a scholar who actually DPSes well. It allows them to get a lot closer to the accuracy cap than they ever could, otherwise.

They're about equal in all fronts, they just contribute in different ways.

[Griffeth]

I wouldn't say Machinist is more versatile.

Machinist can, as you said, buff physical DPS a bit and reduce the damage the party takes.

Bard, in turn, can buff magical DPS and also reduce the enemy's evasion by 10% with a 100% uptime. Rain of Death is critical if you have a scholar who actually DPSes well. It allows them to get a lot closer to the accuracy cap than they ever could, otherwise.

They're about equal in all fronts, they just contribute in different ways.

This is correct. Selection of BRD vs MCH will depend on the rest of the group comp. If you have 2 melee (our group is MNK and DRG) then its good to have the MCH for the 5% physical. If you have more casters (only 1 melee and a BLM/SMN) then it may be better to have a BRD for the 10% magic.