So Faerie Fire is well known as an anti-invisibility spell, but I'm interested in how y'all rule the precise wording of the spell.

For reference, here is the text from the spell I am inspecting:

Any attack roll against an affected creature or object has advantage if the attacker can see it, and the affected creature or object can't benefit from being invisible.

Here is what the invisible condition reads:

An invisible creature is impossible to see without the aid of magic or a special sense. For the purpose of hiding, the creature is heavily obscured. The creature's location can be detected by any noise it makes or any tracks it leaves.
Attack rolls against the creature have disadvantage, and the creature's attack rolls have advantage.

And finally, the rules on how disadvantage and advantage interact:

If circumstances cause a roll to have both advantage and disadvantage, you are considered to have neither of them, and you roll one d20. This is true even if multiple circumstances impose disadvantage and only one grants advantage or vice versa. In such a situation, you have neither advantage nor disadvantage.

So my question is, when you attack an invisible creature that is under the effects of Faerie Fire, do you attack with advantage? I can see it either way, personally. Let me elaborate:

• Faerie Fire not only grants advantage, but is also negates benefits from the invisible condition. That means that the disadvantage from attacking an invisible creature is negated, and also advantage is granted. Therefore, the rule about disadvantage and advantage cancelling out is not relevant, because the disadvantage does not exist.
• The mention of Faerie Fire grants advantage, which is immediately cancelled out by the disadvantage granted from the invisible condition. The added "negates benefits" verbiage is only relevant for the other portions of the invisible condition, such as gaining advantage on attacks made by the invisible creature.

This is a rules interaction that is mentioned a ton but the RAW is a little ambiguous on. (Personally, I think it is unambiguous, but that reading also ups the ante to a point where this is far more powerful than a level one spell should be. I know even without granting advantage on invisible creatures it is a great spell, but negating disadvantage, not just cancelling it out, is something that almost never comes up in DND and therefore would make this even better.)

So, when you attack an invisible creature with Faerie Fire, do you attack with advantage, or as a standard attack roll?

ETA: It is further confused by the "if the attacker can see it" clause of Faerie Fire, which seems to specifically be targeted at how this interacts with invisibility. After all, an attacker cannot see an invisible enemy, and therefore the advantage granted by Faerie Fire might not apply at all. However, that following sentence counteracts that. 

If a creature or object can't benefit from being invisible, then as far as the rules are concerned, they aren't invisible. You have advantage as normal.

Samus is correct.  The reason for the "if you can see it" language is to prevent faerie fire from countering the disadvantage from being blinded (or things that simulate being blinded).

Faerie Fire straight up just suppresses invisibility - which means pure advantage (unless there is another source of disadvantage from something else). The clause in the spell about seeing the target isn't about invisibility - it's about things like full cover - or heavily obscured - or blinded.

I agree. Fairy fire cancels all benefits of invisibility and grants advantage if the attacker can see. So being blinded or fighting in magical darkness still gives disadvantage for attacks that is not cancelled by fairy fires advantage.

The faerie fire outlines objects and creatures in a colored light, blue, green, or violet, that is 10 feet of dim light.

A glowing being that has light emitting from them out to 10 feet is not invisible. This is why the condition of being invisible no longer grants it's effects.

(Incidentally, if you cast detect magic, don't invisible creatures glow with an illusion magic?)

(Oh wait, they don't glow... you see a blue aura. So, basically for you they're not invisible.)

Quote from Brian_Avery >>

(Incidentally, if you cast detect magic, don't invisible creatures glow with an illusion magic?)
(Oh wait, they don't glow... you see a blue aura. So, basically for you they're not invisible.)

Nope. Detect Magic: "you can use your action to see a faint aura around any visible creature or object in the area that bears magic".

Quote from 54MU31 >>

If a creature or object can't benefit from being invisible, then as far as the rules are concerned, they aren't invisible. You have advantage as normal.

 What I was going to say.

Disadvantage is a benefit of invisibility. They lose that benefit, so the advantage runs unopposed.

Thanks all. This is what I expected but I'm still pretty surprised that a first level spell can negate disadvantage (from a particular source) rather than just balance it out! That's impressive, that means this is a +10 swing in some cases (-5 DIS removed, +5 with ADV added) from a super low level.

Quote from NVCoach >>

Thanks all. This is what I expected but I'm still pretty surprised that a first level spell can negate disadvantage (from a particular source) rather than just balance it out! That's impressive, that means this is a +10 swing in some cases (-5 DIS removed, +5 with ADV added) from a super low level.

 … if they fail the Dex save and don’t disrupt the concentration of the caster for the whole time.  

Invisibility isn’t meant to be completely overpowering, it’s meant to have a counter to it.  In older editions, Invisibility was more like Frodo’s ring, a super-powerful condition that allowed you to do almost anything without being noticed. 

You also need to be really careful where you put it - or the strength based Paladin in your group's going to get lit up like a Christmas tree. Faerie Fire isn't picky about who it hits.

Interesting! I’ve mostly used faerie fire to avoid blur, not invisibility.