Shield of faith vs Protection from Evil and Good.

[Aussiehams]

G'day all.

After 9 levels, I just discovered Protection from Evil and Good for my Pally.
Other than the casting time is their any benefit to shield of faith if you know you'll be fighting fiends, undead etc.?
I'm wondering if I'm missing something, or if I've just been casting the wrong spell for ages?

[sithlordnergal]

Shield of Faith is better in a few occasions:

1) Your opponents already have disadvantage when making attacks against you. This could be due to spells, magic items, the Frightened condition, or anything really.

2) You have low AC. Disadvantage won't help much if your AC is already low, and a +2 can make a huge difference at times

3) You need to give an ally some sort of protection, but they're out of touch range

Outside of that, Protection From Evil and Good will generally be better in the situation you described.

[Nhorianscum]

G'day all.

After 9 levels, I just discovered Protection from Evil and Good for my Pally.
Other than the casting time is their any benefit to shield of faith if you know you'll be fighting fiends, undead etc.?
I'm wondering if I'm missing something, or if I've just been casting the wrong spell for ages?

Pretty much just casting time. There are (as seen above) some edge cases where SoF is better but those are hens teeth.

[Greywander]

2) You have low AC. Disadvantage won't help much if your AC is already low, and a +2 can make a huge difference at times
I did the math once, and the conclusion I remember coming to is that if an enemy hits you on a 5 or higher, then imposing disadvantage is better than +3 AC (the comparison was a Cloak of Displacement vs. armor +3), whereas if an enemy hits you on a 4 or less, +3 AC is better.

Generally, the more AC you have, the more valuable another +1 AC is, but imposing disadvantage also becomes more valuable as your AC gets higher, and it scales faster than AC bonuses do. If an enemy needs a 19 to hit, then +1 AC means 50% fewer hits, but disadvantage means 90% fewer hits. If an enemy hits on an 11, +1 AC is 10% fewer hits, while disadvantage is 50% fewer hits. The Cloak of Displacement is actually one of the strongest defensive items you can get (Cloak of Invisibility is the natural upgrade, and helps with offense, too).

So short version, PfE&G will be stronger than SoF in almost every situation where it applies. But PfE&G doesn't apply to every situation, and as sithlordnergal said, you might have other ways to give disadvantage, in which case PfE&G is redundant and SoF becomes a lot better.