How does Baby-Doll Eyes compare to Charm?

Baby-Doll Eyes is a Fairy-type move introduced in Gen. VI that reads as follows:

The user stares at the target with its baby-doll eyes, which lowers its Attack stat. This move always goes first.

The move Charm has been changed from Normal to Fairy in Gen. VI.

The user gazes at the target rather charmingly, making it less wary. This harshly lowers its Attack stat.

Baby-Doll Eyes is 30 PP and Charm is 20 PP.

While Charm's "harsh" status is often preferred, I'm unsure whether or not that makes it more or less advantageous than Baby-Doll Eyes's ability to always go first. How do these two moves compare to each other and in what situations would one be more advantageous than the other?

In my specific case, I have Charm already on my Eevee, which I would eventually like to evolve into a Sylveon. I only need one Fairy-type move to meet that requirement and having both of them would feel redundant. While I don't plan on doing any competitive play, both regular gameplay tips and any relevant information for competitive play (if there is any to be had) would be appreciated.

Solution 1:

Since you say that you're going to evolve Eevee into Sylveon, let's look at Sylveon in particular:

Sylveon has a base Speed of 60. Unfortunately, this means that Sylveon falls well below the average base Speed of most Pokemon. This contrast is well illustrated by comparing Sylveon to Eevee's other evolutions, such as Jolteon's base speed of 130 (the fastest of Eevee's evolutions) and Umbreon's base Speed of 65. In fact, Sylveon has the lowest base Speed of all of Eevee's evolutions.

This means that if you choose Charm, you will most likely go after your opponent. Therefore, your opponent will have one turn to attack with their full power, after which Charm will lower their Attack by two stages, or 50% power. So, if Sylveon can take that initial full power hit, Charm is preferable. Unfortunately, Sylveon specializes in absorbing special-type attacks, not physical. Her base Defense, sitting at 65, is half of her incredible base 130 Special Defense.

Therefore, Sylveon won't be able to tank full-powered physical moves very easily. This is where Baby-Doll Eyes' priority comes into play. Sylveon is much more likely to survive 2/3-powered physical hit as opposed to a full-powered move.

Solution 2:

Harshly/Sharply degrading a move has double the effect of just raising/lowering a stat, to the effect where a Charm will drop your opponent's attack to 50%, while Baby-Doll Eyes cuts their attack to 2/3rds. Both are pretty significant drops. You can drop (or raise) stats up to 6 stages, which is only 3 uses of Charm but 6 uses of Baby-Doll Eyes (that's generally quite excessive though).

So generally Charm is better unless you really need to go first, since the effect lasts the duration of the opponent's time in play (baring their status being healed, rare in trainer fights). But if you're about to take a heavy hit and don't know if you will go first, or know you won't, Baby-Doll Eyes can dull a blow immediately (it's priority is probably +1 but we don't know exact priority tiers for gen 6 yet).

And of course whether you use either depends on whether you'd be safer by dropping a target's attack than by just hitting them as hard as possible or buffing your own attacks. Such moves are only useful in fights where a single pokemon is going to remain in the fight for several turns.

Note that, competitively, stat reducing moves are generally not seen (not those that don't also deal damage or cause status effects, anyhow). The problem with decreasing stats is that switching out removes all "stages" of stat boosts/drops, so by harming an opponents' stats, you leave them in control of the situation, whereas by buffing your own stats (raising your defense instead of lowering their attack) you're in control of when you switch (though not necessarily of when you get KO'd).

NPCs on the other hand behave very differently and will almost never switch out pokemon outside of the Battle Maison and Battle Institute, so you can freely drop most Trainers' stats and they'll act fairly oblvious to this.