I've seen people recommend Volcanic plate, Vog cub, and Divine robes, but I've almost never seen the Plate mail being used, is it worse then the others? And if so is it still usable? Also I wanted to know about the ancient plate mail, is it completely useless, or can it still be used, just with a bit of difficulty?
EDIT: For the first three is should be noted that I'm talking about for FSC
EDIT EDIT: I also forgot to ask about the volcanic demo set, -.- Is it viable as well?
I think people stay away from the plate sets because of the attack speed decrease. SK is balanced in the late game towards attack power and dodging rather than any sort of tanking, so the plate sets don't really fill much of a role there.
However, I personally think they can be useful when paired with some of the split-special armours like the divine set. IE: volcanic plate mail and divine veil as a set for FSC. If you choose to go down this route, however, you'll have to be very conservative with taking multiple swings at enemies as you'll more often than not lose the race between you interrupting or knocking them back, and them completing their attack.
I just got my ancient plate helm so I can't comment much on that set yet; I haven't even equipped it. I'm mostly planning to use it as part of a novelty set for T3 lockdown bombing, since bombs are minimally (if at all) affected by ASD. I'm also considering pairing it with my swiftstrike to erase the ASD and using it as my "I'm the juggernaut, b*tch" set for clearing T1 and T2 in profitable gates.