Direct usefulness for BRD without concern for whether or not you should get it:
Osode: basically pulling gear. Was tanking gear too pre-Mazurka hate nerf.
Errant/AF+1: what you wear for most endgameish stuff, since it has beefy CHR and -enmity. AF+1 also doubles as pulling gear as well.
Minstrel's Coat: if you have plenty of CHR elsewhere, the 3 skill may edge out one of the 10 CHR bodies. Usually, however, body is one of the main slots to get CHR, and you do need *some* (just not ridiculously huge amounts). So, situational debuffing piece.
Yigit/Manteel: macro in for buffs (casting speed is determined when you *start* casting, unlike most magely stuff which is determined when the spell goes off). Yigit doubles as hMP gear too.
Vermy/Dalm: only ever useful with mage sub, of course. Vermy's a reasonably justifiable purchase. Dalm is an improvement, with more MP and a freed-up head slot.
AF2: lolmeleeBRD.
Marduk: Salvage gear nuisance aside, this is basically debuffing gear + dalm/vermy wrapped into one (though you'd want to throw on something with more -enmity for endgame stuff, when not actively debuffing), with a bit of fast cast (of yet unknown amount) thrown in as well. Rare enough to not really be applicable yet.
Relative to other stuff:
Osode: not many jobs have a huge claim on this any more (RNG and BST are notable for getting mileage out of it), but it's still at least a macro piece for most of them. I'd give it to a dedicated BRD over a newbie something-that-can-use-it-better, but otherwise I'd prioritize usefulness, and BRD doesn't get much out of it.
Errant: buyable, not applicable.
AF+1: job-specific so technically not applicable, however getting AF+1 body means *not* getting AF+1 hands or legs, which offer somewhat less replaceable stats (i.e. beefy +skill). Also costs a reasonably hefty 40 coins. So even a BRD who does Limbus regularly might not be getting this for a while.
Minstrel's Coat: uninteresting to any job except BRD, really, so not applicable.
Yigit: spend your Assault points on whatever you like, not applicable.
Manteel: job-specific so not applicable, however it's worth noting that it's bloody expensive if you don't have the option (shell that does Vrtra or Bahamut v2) of getting one free. Yigit is effectively comparable.
Vermy: buyable so not applicable.
Dalmatica: WHM and BLM and SMN all have better and more accessible options, really. RDM gets more mileage out of the refresh, the MP, and the freed-up head slot, than BRD does. Again, best for something like this to go to a dedicated BRD over a newbie RDM, but otherwise RDM > BRD > others.
AF2: job-specific so not applicable, also lolmeleeBRD.
Marduk: same argument as Dalmatica about the auto-refresh bit (read: WHM and SMN have better *and* more accessible options), and otherwise the stats (on this particular piece) are more interesting to BRD than to the others.
Summary:
For reasonable effectiveness, Errant (debuffing, -enmity), Yigit (-cast time, resting MP), and Vermy (refresh) are all a BRD really needs (oh, and something with def/VIT to wear for pulling). AF+1, Manteel and Dalmatica are nice improvements respectively (noting that Dalmatica is better off with RDMs in general, and AF+1 serves as very nice pulling gear), but are ultimately little more than luxury. Marduk would be well worth considering if it were more accessible, as-is it's more in the pipe dream category still.
For a fresh high level BRD, Errant and something non-squishy to pull in (such as Cardinal Vest or something) is just fine for starters, and you can expand from there (doing Assaults for Yigit isn't too hard). Don't go nuts over Osode unless you're also getting it for some *other* job, it doesn't do much for BRD.
