Defensive Duelist vs. Shield

[Fwiffo86]

The name says it all. I'm looking for a comparison. Math included.

Plate + Shield + Defensive duelist
vs.
Mage Armor + Dex + Shield

Straight up non-math comparison:

Defensive Duelist:
18+2+6 = 26 at level 20

Shield:
13+5(dex?)+5 = 23 at level 20

I'm curious how this stacks up mathematically as far as damage reduction percentages. Plus any other thoughts as well as possible Dex (light armor) configurations.

[Shadow]

I think the main thing to consider here is that the defensive duelist can use his reaction every single turn all day long, while the caster needs to use a spell slot to get his shield. So not only is the caster lacking in comparative AC slightly, but he is also lacking in the number of uses he'll get out of it.

The spell is much better at earlier levels than the feat is, but that also comes with the added oppportunity cost of not having the spell slots to spare at those earlier levels.

[Fwiffo86]

I think the main thing to consider here is that the defensive duelist can use his reaction every single turn all day long, while the caster needs to use a spell slot to get his shield. So not only is the caster lacking in comparative AC slightly, but he is also lacking in the number of uses he'll get out of it.

The spell is much better at earlier levels than the feat is, but that also comes with the added oppportunity cost of not having the spell slots to spare at those earlier levels.

Agreed. However, this is a level 20 comparison. So to make life easier, I am assuming the Wiz (only wiz) has selected Shield as one of his at wills.

[Yorrin]

Agreed. However, this is a level 20 comparison. So to make life easier, I am assuming the Wiz (only wiz) has selected Shield as one of his at wills.

If that's the case

Plate = Mage Armor + 20 Dex
Defensive Duelist + 20 Dex = At Will Shield Spell

So the only difference is the ability to use a physical shield with Plate for +2AC.

[Shadow]

Agreed. However, this is a level 20 comparison. So to make life easier, I am assuming the Wiz (only wiz) has selected Shield as one of his at wills.

Then it's a no brainer. Shield spell wins, hands down.
23 AC is tanky as heck, especially for a caster (those extra 3 points would be nice and all but they aren't needed), and that 23 AC is always active as opposed to the defensive duelist having 26 for a single melee attack only. For all other attacks, ranged included, his AC is 20.

But this doesn't become a true no brainer until 18th level....

[MaxWilson]

So the only difference is the ability to use a physical shield with Plate for +2AC.

+1 from Defensive Fighting Style, which doesn't work (as I read it) unless you are wearing actual armor. So +3 total for the fighter.

[Easy_Lee]

Then it's a no brainer. Shield spell wins, hands down.
23 AC is tanky as heck, especially for a caster (those extra 3 points would be nice and all but they aren't needed), and that 23 AC is always active as opposed to the defensive duelist having 26 for a single melee attack only. For all other attacks, ranged included, his AC is 20.

But this doesn't become a true no brainer until 18th level....

It also depends on how many attacks would have gone through that round otherwise. Many have suggested that at AC 20, it's unlikely that more than one attack is getting past your defenses that round anyway. It depends on exactly what we're fighting.

[Sartharina]

Then it's a no brainer. Shield spell wins, hands down.
23 AC is tanky as heck, especially for a caster (those extra 3 points would be nice and all but they aren't needed), and that 23 AC is always active as opposed to the defensive duelist having 26 for a single melee attack only. For all other attacks, ranged included, his AC is 20.

But this doesn't become a true no brainer until 18th level....
AC 23 is worthless without the HP to back it up (You WILL get hit) - compare AC to monster attack bonuses. And those extra 3 AC points help a lot more than you'd think, by pushing more monsters off the bottom (Tip - no monster I'm aware of has less than +4 to attack), and being more reliable against high-attack-bonus enemies.

[Demonicattorney]

One of these two doesn't get you mage-slayered into oblivion (if your DM uses those type of things). Also Anti-Magic field, Counterspell etc.

Not that it matters because someone with 20 levels of Wizard has literally half the HP of a Fighter, so even if the ACs were equal (which they aren't), the defense is worth less than half.

Also, I'm pretty sure the level 20 at-will ability will be errated to spells that take an action to cast. Its clearly not intended to allow you to cast shield every round (which is head and shoulders the best option).

[Easy_Lee]

One of these two doesn't get you mage-slayered into oblivion (if your DM uses those type of things). Also Anti-Magic field, Counterspell etc.

Not that it matters because someone with 20 levels of Wizard has literally half the HP of a Fighter, so even if the ACs were equal (which they aren't), the defense is worth less than half.

Also, I'm pretty sure the level 20 at-will ability will be errated to spells that take an action to cast. Its clearly not intended to allow you to cast shield every round (which is head and shoulders the best option).

It and misty step. Also, an abjurer's ward may fix the HP difference.

[MaxWilson]

AC 23 is worthless without the HP to back it up (You WILL get hit) - compare AC to monster attack bonuses. And those extra 3 AC points help a lot more than you'd think, by pushing more monsters off the bottom (Tip - no monster I'm aware of has less than +4 to attack), and being more reliable against high-attack-bonus enemies.

Hobgoblins have +3. Steam Mephits have +2, some of the other mephits have +3.

[MaxWilson]

Its clearly not intended to allow you to cast shield every round (which is head and shoulders the best option).

For a standard, non-gish wizard I'm actually not sure that Shield IS the best option. How often do you take a direct attack anyway where Shield would make the difference? Ideally you're out of range and busy summoning conjured creatures/animating undead/casting Foresight on other people (to the extent that the Concentration economy still allows such things). I can see at-will Disguise Self getting more casts than at-will Shield would in a number of situations, and Grease can be good in combat too (doesn't take Concentration).

Fortunately you don't have to choose though, you can swap out your spell mastery as the situation demands. So you can have Disguise Self when needed and Shield for dungeoneering.

[Rilak]

The problem with defensive duelist is that it works against a single attack per turn. Monsters at higher levels have multiple attacks. Shield scales really well at higher levels, potentially giving you +5 AC against all attacks you are ever going to take (level 18 Wizards can use it every round they are hit). Shield also works against ranged attacks and spells.
If your AC is good enough, you won't trigger the ability to take a reaction and use the spell slot if you need to conserve spell slots.