I was using the nibiru clubs for a while but now is using 2 iris swords. I like them for the added fastcast. +14 fastcast and +60 blue magic skill using path d.
Path D
"Blue Magic Skill"+15
"Magic Accuracy+15
"Magic Attack Bonus"+15
Iris will be lower damage output than Nibiru Club. Make sure you keep in mind that Iris does not have actual "Fast Cast" on it. "Blue Magic spellcasting time -7%" does not affect your recasts. That said, I normally use Iris+Nibiru when AOE'ing (since I've yet to get an extra Colada for nuking augs.) I find being able to engage>Sanguine Blade very reassuring for those WTF moments where I actually get interrupted.
Colada will lose to nibiru from a pure damage perspective right?
Excluding DM augs, an average Colada would probably still lose, but not by very much tbh, and the benefits of having a sword in main-hand should outweigh a few hundred dmg per 12k nuke IMO. Not sure where a DM-aug'd nuking Colada would fit in since it should be possible to get some pretty crazy stat combos, but a "perfect" one would definitely beat Nibiru Cudgel.
For ease of comparison, here's the nuking stats for the weapons in question, with appropriate/reasonable augments:
Nibiru Cudgel, PathB: MP+50, INT+21, MND+11, MAcc+7, MAB+31, MDmg+124, MAcc Skill+215, (Cure Potency+10%, does affect BLU heals)
Iris, PathD: MAB+29, MDmg+108, Blue Magic Skill+30, MAcc Skill+201, Blue Magic casting time-7%, (Chain Affinity +25, only matters for phys spells)
Colada, Taupe: INT+12, MAcc+30(+15), MAB+29(+15), MDmg+123, MAcc Skill+201, Fast Cast+7%(+3%)
So actually, looking at what I just typed, it seems that if you have a good amount of INT otherwise, I think that a "perfect" non-DM Colada should actually beat Nibiru. I also don't know if Colada can get both types of MAcc/MAB augs at the same time like armor can, so assuming a cap of +20 on each. The lack of INT on Iris is what kills it as a true contender, but it still performs decently enough to be an option in the meantime.