I can class armors and helmets to three catagories:
-Performance enhancing gear (increases the attack performance of one type of weapon)
-Scenario gear (increases the damage affinity for one type of monster or clockwork level)
-Regular gear (normal gears with no special perk what is so ever)

Now by using my Utility calculator:
+0.5 if the armor has a resistance to any of the three types of damage (piercing, elemental and shadow)
-0.3 if the armor doesn't have normal defence
+0.3 if the armor grants a med CTR to one type of weapon
+0.3 if the armor grants a med ASI to one type of weapon (and vice versa if there is a med ASD)
+0.3 if the armor grants a med damage bonus to any of the monster race(and vice versa if the armor offers any penalties)
+0.2 if the armor offers a status that is resistance to a particular clockwork level with a monster type that the armor is resistant to(and vice versa if the armor has a weakness)

I can calculate the 'utility value' of a certain gear. Mean by Utility, I mean just how useful a set is and how many different clockwork levels can it be used in. But first let's make a few assumptions.

1. This calculator assumes that a player will always dress correctly to the party, that means, a fallen set doesn't give you bonus in fire deconstruction site, since Gremlins are elemental.
2. Sleep is a dead status, hence the jelly set will not gain score for the sleep resist.
3. UVs, Health bonus and MSI are not accounted in the calculation due to it is really up to a player to place him/herself in the right palce during battle and manage their health accordingly.
4. All gears are measured at their 5* or final version, this calculator only applies to shields and armors.

Now I will use this to compare the usefulness of two set of amor, the valkyrie set vs. the shadowsun set

Valkrie set:
+0.5 shadow defence
+0.3 X 2 for VH fiend damage bonus for sword
+0.3 X 2 for VH fiend damage bonus for gun
+0.3 X 2 for VH fiend damage bonus for bombs
+0.2 X 5 for clockwork levels of the following, waste work-infernal passage, waste work-haunted passage, candle stick keep: noxious night, devilish drudgery: toxic work place, grave yard.
-0.2 X4 for the clockwork levels of the following, Balst furnace-infernal passage, Balst furnace- haunted passage, candle stick keep: burning blackout, devilish drudgery: everybody's fired.

Overall utility value: 2.5

Shadow sun set:
+0.5 shadow defence
+0.3 X 2 for VH fiend damage bonus for gun
+0.3 X 2 for VH undead damage bonus for gun
+0.2 X 4 for clockwork levels of the following, waste work-infernal passage, waste work-haunted passage, candle stick keep: noxious night, devilish drudgery: toxic work place.

Overall utility value: 2.5

For those you that see this calculator, try it out, and see if there really is a big difference between performance enhancing gears and scenario gears.