I dont see why this wouldnt be a bad for BST, As long you have the +ACC to back it up. Fighting EM to lower VT a Meat build(Pure ACC) would work very well. I woulnt use this unless as i said the gear to back it up E.g: Peacock.Charm/Armlet, Snipers/WoodmensX2, Potent Belt/Life, O.Hat.
There are many reasons this is an inferior choice to the Haubergeon/Hauberk etc. Note that all jobs listed can also use Haubergeon.
1. When you gear for Haste, you need accuracy somewhere. You're sacrificing potential accuracy on slots such as the waist slot and the hands slot. A haste build is superior to a str/atk build, and even with merits, you need accuracy SOMEWHERE. Haubergeon's +10acc and +5dex is an incredible asset to building accuracy, which allows a Haste build to hit full potential. And yes, a Haste build will do far more for you than ~10 attack difference will do.
2. Food choices. If you wear Haubergeon to make accuracy high enough to eat meat, you are getting far more Attack over sushi than the ~10 difference. It's not worth it!
3. Evasion only works well when stacked. In the case of NIN, you're either gonna need lots of evasion or not much -- there shouldn't be an in-between. Byrnie simply doesn't fit in.
Why would you complain about ppl "down rating" others who choose a haub. Really?! In the end, it breaks down to how a piece of gear is used vs gear swapping setups, and all round... players choice. It was a recommendation. I use both, and myself, i prefer the Byrnie. So rather than bash your head over your keyboard because someone gave an opinion you dont like... get over it :o
Why would NIN want this over a Haubergeon? You've got an A- weapon (without merits and who merits Katana with more than one 75 job), so the Accuracy helps. All of the end-game Katana WS are DEX-modded too, as much as STR. Byrnie (STR+3 DEX-3 Atk+20) vs Haubergeon (STR+5 DEX+5 Acc+10 Atk+10); is Atk +10 worth losing STR+2 DEX+8 Acc+10? In the end, the only appeal I can think of for a Byrnie is looking orange. ;o
I chose this to use til level 75 SAM. Yes its true sometimes the Acc lets it down, but I think it totally depends on how you wanna play. I found this piece good for Campaign Battles too, I don't seem to need much accuracy during them even after update so its nice for that and I campaign battle more than party atm.
Also its really cool looking XD
Choices are half of the fun!
Hauby or Byrnie either way you know you got a great piece of body armour
Inferior for TP gain, but with the new +15 WSAcc +10 Acc Moogle addon head, and a little math to check that accuracy is still capped, this becomes second to Plastron for AH'able Guillotine body pieces.
Capped accuracy is critical, however, because Guillotine will always miss at least one hit 18.5% of the time, but Guillotine at 90% accuracy will miss a hit 30.7% of the time. Find the necessary amount of accuracy for a target mob and the MKD head will let you throw on so many more pure damage pieces.
This is pretty situational depending on what kind of DD build you have. I've seen PLD/WAR, NIN, SAM/DRG and DRK/DRG with some pretty nasty attack/haste builds put out some nice damage with a Byrnie. But if accuracy is still an issue, I'd recommend the Hauby/Hauberk over the Byrnie just for general purposes.
Byrnie is nice for BST since BST don't really use a Haste setup. and the ACC the Hauby adds isnt' much of a factor when you're fighting EM - low VT's, this adds 1 more def and 3 vit for when you take hits as BST, which you will, you gain 2 more agi and 20 more evasion in this over hauby for evading or parrying. This is probably better for the BST, but all in all it really comes down to personal choice.