all of this is my opnion but here it is
from worst to best
Ikzati dress: doesnt exel in anything and provides resistances AFTER you needed them
Asira's wing: kinda weak but using it on your off-hand prevents disarms from your main hand, good for the effect not the stats
Caranbrot: previously ridiculously overpowered effect now underpowered, still it has good stats just the special effect is weak (scales with toughness too)
Panoply: special effect making you sunder immune is good but isnt unique to it... the TEN FUCKING INITIATIVE ON THE OTHER HAND...
i consider the panoply good mostly because it basically garantees you go first and on a turn based combat going first is a huge advantage
it has "meh" armor/ward/focus... HOWEVER the resistances are terrible, Holy is rarely used against us and Blight is often used against us
i would boil down these items to
pick Panoply if you want +10 initiative with sunder immune as a bonus but doesnt want/need a armor piece with high defensive stats
pick Asira's wing only if you dual wield and doesnt want to be disarmed
pick Caranbrot if you play with Two-Handeds and its better than your current one
Ikzati... its not even the best spellcaster robe.... pick it if you think dresses are pretty?