Was Snape better at Potions or Defence Against the Dark Arts? [closed]

Question

We know Snape has been an excellent Potions-master at Hogwarts and he has always wanted to be the DADA teacher

Which Dumbledore appoints him in HBP to make way for Sluhghorn.

Given that he is also

The Half-Blood Prince. Which was said by even Slughorn (via the copying of Harry) that his potion work is the best he's ever seen.

Would he be considered better at Defence Against the Dark Arts or Potions?

EDIT:

I should clarify that I mean in general, not just in his role

or roles

but also in practice.

Is he better at performing Defence Against the Dark Arts or making Potions as a whole?

Answer 1

Snape was undoubtedly an excellent Potionsmaster -- I believe his aptitude for potions is inarguably recorded for posterity in the copy of Advanced Potions Making that Harry ultimately receives in Half-Blood Prince. The incredible nuances Snape possesses for Potions is advanced beyond the skill levels of any of his classmates that we know of, the possible exception being Lily Evans, whose Potions skills Slughorn repeatedly raves about to Harry. For example, when Harry wins the Felix Felicis in Half-Blood Prince, Slughorn says:

‘The clear winner!’ he cried to the dungeon. ‘Excellent, excellent, Harry! Good Lord, it’s clear you’ve inherited your mother’s talent, she was a dab hand at Potions, Lily was!’

_{Half-Blood Prince - Page 181 - Bloomsbury - chapter 9, The Half-Blood Prince}

We don't exactly know if Lily was equal to or better than Snape at Potions from canon, but judging from Snape's copy of Advanced Potions Making, I'm going to err on the side of Snape being the superior student; this doesn't mean that Lily wasn't excellent at Potions too.

Throughout the series, if I recall correctly, Snape never once makes a mistake while teaching or preparing Potions.

I think Snape's skill at Defense Against the Dark Arts is very prodigious. Sirius tells Harry that Snape arrived at Hogwarts as a first year knowing more curses and dark magic than most seventh years would. As a sixth year, Snape is able to manipulate magic to create new spells -- Sectumsempra, etc. His spells are recorded in the margins of his Advanced Potions Making book. He was attracted to dark magic; that tells me (YMMV) he possesses an inherent affinity toward the dark arts. So at the very least, Snape knew the subject matter.

But he makes a few mistakes.

‘Pathetic, Weasley,’ said Snape, after a while. ‘Here – let me show you –’

[Snape] turned his wand on Harry so fast that Harry reacted instinctively; all thought of non-verbal spells forgotten he yelled, ‘Protego!’

His Shield Charm was so strong Snape was knocked off balance and hit a desk. The whole class had looked round and now watched as Snape righted himself, scowling.

_{Half-Blood Prince - Page 171 - Bloomsbury - chapter 9, The Half-Blood Prince}

In Order of the Phoenix, Snape leaves his worst memories accessible to Harry:

[Harry's] breath was actually fogging the surface of Snape’s thoughts ... his brain seemed to be in limbo ... it would be insane to do the thing he was so strongly tempted to do ... he was trembling ... Snape could be back at any moment ... but Harry thought of Cho’s anger, of Malfoy’s jeering face, and a reckless daring seized him.

He took a great gulp of breath, and plunged his face into the surface of Snape’s thoughts.

_{Order of the Phoenix - Page 564 - Bloomsbury - chapter 28, Snape's Worst Memory}

As well, Snape fails to teach Harry Occlumency in general.

In Half-Blood Prince, Snape is unable to access Draco's mind via Legilimency. Snape is a fully grown man and an accomplished Legilimens, while Draco Malfoy is a sixteen-year-old boy who's only received Occlumency lessons from his nutty aunt. Snape should have been able to break through Draco's thoughts.

In Deathly Hallows, as headmaster, Snape allows his Dark Arts teachers to have the students practice dark magic, including at least one Unforgivable, on their fellow students, and allows the dark arts to be actively taught to the students. As Potionsmaster, pretty much the worst thing he does is mess with Neville's mind regarding Neville's toad Trevor and forcing Neville to test his shrinking solution on Trevor (Neville of course being terrible at Potions; Trevor could have been rendered a tadpole forever!).

For these reasons, I think canon demonstrates that Snape was a better at potions than he was at DADA, both practically and as an instructor.

Answer 2

His skills as a potion-maker cannot be denied, nor can his skill at combative magic. Snape is undoubtedly one of the better non-Auror wizards when it comes to knowledge and ability in curses, their counters, and the art of magical combat.

He is also one of, if not the single best, potion maker in the series.

So to answer your question: Neither, as a teacher. Snape is equally terrible at both posts for one undeniable reason: he's an awful teacher.

Simply knowing your subject is only part of the job of teaching, as Professor Binns demonstrates. Much more important is the ability to ably convey what you know to your students. You must be able to make them understand what they're doing and learning. You must be able to engage them. You must be able to adjust your materials based upon the needs of your students.

Snape tries to do this, but utterly fails. He is constantly sidelined by his personal desires for revenge upon the House of Gryffindor and Harry, son of James, in particular. He goes out of his way to favor his Slytherins and belittle the other houses (especially Gryffindor). Every student in the school knows it, and it can clearly be seen to impact his ability to teach a class.

How many students drop Potions like a bad habit as soon as they can? How many classes get sidelined by 10-minute long rants on how a particular student isn't exceptional? No good teacher would allow such things to happen with any frequency - they'd want students to love their subject and enjoy their classes. For Snape, it seems to happen at least weekly. He may have tried slightly harder in DADA, but his terrible habits couldn't be broken.

Whatever else Snape was - hero, traitor, potion maker, fighter, all of that and more - he was undeniably a horrible teacher.

EDIT:

To re-answer, based on your edits and clarifications:

Snape was, as I said, excellent at combat magic. He is, overall, a magical powerhouse. He's also talented. He is Occlumens enough to defeat Voldemort. He can fly without broom or thestral, yet his combat powers pale before Dumbledore or Voldemort. They were his clear superiors. Snape, possibly, could have beaten either of them if he'd had time to prepare and caught them unaware. They, however, could have defeated him without preparation or underhanded tricks. Ergo, he is clearly not the undisputed master of combat magic.

If you consider potion making, on the other hand, he is clearly the greatest brewer of potions in the series. He may not be the greatest in the world - we don't know for sure. What we do know, however, is that Voldemort was never seen to mix a potion (he instructed Wormtail in the creation of one, but may have been lying when he claimed to have invented it). Further, Voldemort never made extensive use of potions - possibly considering them beneath him or fit only for traps.

Dumbledore, however, was an alchemist of some note. He worked with Nicholas Flamel to discover uses of Dragon's Blood, after all. It's unclear if any of that skill translates to potion making, but it gives us a meter stick. Dumbledore was versatile and could do almost any magic that needed to be done. But when he needed a potion? He always turned to Snape. Clearly, Dumbledore saw Snape as the superior brewer of potions.

Therefore, by the only reasonable measure (his relative skill vs his peers) Snape was clearly better at brewing potions as opposed to combative magics (DADA).