@Jarkes  
that would explain why it sucked so hard.

What if Sunset and Twilight are close to the same age and both were/are Celestia’s students, but Celestia kept them separate for Celestia reasons and some 2.5 or 5 years (or another multiple of thirty moons, and that’s terrible) before EQG happens, Sunset leaves to Urf to try and take over that world (Of Course!).

@Jarkes  
Ah, that would explain it.

@Vinyl Fluff
 
They reduced what should’ve been an epic battle for the fate of Equestria… into a f***ing American Idol parody.
 
To be fair, though, that particular one was literally written at the last minute because Hasbro nixed their plans for a Discord Fiendship issue.

@PonyPon  

 
Ah, thanks. I couldn’t remember if it was that one or the RR adaption.
 
Yeah, that could’ve been a lot better. Instead they made them out to be stupid and goofy.

@Vinyl Fluff  
It was the very stupid Siren fiendship issue.

@DragonWraith  

 
I haven’t read the whole thing, but I think it’s the comic book adaption of Rainbow Rocks. Starswirl banishes them, and they get tossed 1000 years into the future. So they arrive immediately before Twilight. This was long after the fanon theory of them being the original sirens. So blagh.

@Vinyl Fluff  
I haven’t read any of the comics, and I’m also a fan of the sirens being the source of the classical Greek myths.  
It requires a bit of jiggling, but I don’t think the two theories are necessarily mutually exclusive.

@DragonWraith  

 
I really like the idea that they arrived there at the exact same time they were exiled from Equestria, so they were the source of the original Greek siren myths. With the negative energy they fed on keeping them young.
 
I don’t like the time-shift explanation given in their comic. I really don’t like the idea that they literally went from Equestria to Earth and it’s only been a few days since they arrived before Twilight came back.
 
@MadVillan  

 
We’ve got a hint during Dash’s birthday. There are 25 candles on her cake, implying she’s 25. This doesn’t tell us Twilight/Sunset’s ages but we know the mane 6 are not too far apart in age (we know canonically that Pinkie is a year younger than Fluttershy.) So that gives us a starting point for Twilight’s age.

@MadVillan  
It’s not explained anywhere, but my personal theory is that there’s a time dilation/shifting effect (or even, given the nature of magic, an age dilation effect) when you pass through the mirror.  
This would also explain why the millennial alicorns are represented by women in their late 30s/early 40s.
 
The jury’s still out on how long the sirens have existed in the human world, but that would be an important clue to figuring out what’s going on.

@DragonWraith  
@PonyPon  
That brings up the question how old is Sunset/Twilight and how long where they students of Celestia? If Sunset’s old enough to not only become her student first, then go into exile all before even Twilight became her Student then she’s significantly older, at least 10 years. So it’s actually really weird for them both to be Highschool girls in the movie.

@MadVillan  
I guess Sunset’s the definition of the word rusty.
 
She’s out of practice, and has no study resources and practice is pretty much all the other two do on their downtime, and I hardly need to point out how much they have in terms of resources.

Obviously Sunset almost was reached the Twilight unicorn magic power. But Celestia discovered her dark intentions and was banished. Starlight only wants revenge and she studied attack and defense magic spells, plus techniques to mix them. Twilight has more raw magic. But she likes history, organization library, equestrian ethnography. She’s like Gohan.
 
So according to this the level magic is: Alicorn Twilight > Starlight >= unicorn Twilight >= Sunset Shimmer

@MadVillan  
I had never heard of him either.
 
Of note are the facts that A) he’s a director, not a writer, and B) he’s not been involved at all in seasons 4, 5, or (presumably) 6.

Staff tweets =/= canon. Mostly a personal opinion of something they may or may not have discussed. I don’t even care about this debate.

Am I the only one who had to google who Ishi Rudell was? As for story-wise I don’t really see how this makes sense. Starlight was even more determined and driven to learn magic than Twilight ever has been and even went to extreme measures to improve herself. They both have cutiemarks that specialize in magic, but Twilight’s just better just because.
 
Oh yeah, and Starlight too why not.

I wish alicorn Twilight actually had notable feats compared to her unicorn form. I’d be (almost) perfectly okay with Sunset and Starlight being her near equal (even if apparently Sunset isn’t), but only if Twilight was a unicorn.
 
As it is, she was more impressive as a unicorn, especially in season 3.
 
@Softy  
All of those will never be relevant in FiM. Ever.
 
In fact it’s never relevant in any work of fiction I’ve come across… it’s pointless to discuss power levels and battle outcomes.
 
I still like doing it though, it’s fun sometimes.

@Softy
 
Exactly. Dragon Ball Z’s “power level” stuff was meant to deconstruct that in exactly the way you describe, yet somehow it became the most famous example of “power levels”.

Why do people want to reduce a character’s prowess to just a number?
 
Magic isn’t “I’m stronger therefore I win”. There’s probably raw energy produced, the efficiency of the spell, speed of spellcasting, accuracy of the spell, duration, ability to multicast, “refractory period”, among other measures. Then there’s specializing in defensive (and that gets sub-typed into escape vs stand-your-ground) and offensive magic.
 
And even if you can sort all that into some kind of matrix for computing, there are still external factors like location, element of surprise, distractions, etc.
 
That’s why “Who would win.” is kinda stupid unless you weave the whole detailed story leading up to the moment battle.

Sunset was shown to be just a friendless Twilight, so to hear that she’s not just as magically strong is quite a shock. The timeline also confuses me, but she should be a few years older than Twilight, if not several years, so she could have been even stronger. Sure being hornless for so long probably did not do her much good, but, how is she “no where near” Twilight?? It’s her special talent, she was born to become a princess and replace Celestia.
 
Starlight’s magic is just mad though. But then she is another what-if-Twilight. Specifically, the what-if-Twilight did not become a princess, but just kept focusing on magic. She’s what Twilight nearly was. I’m okay with her being so damn strong.
 
@Macaroni C-Pony  
Yamcha is the weakest fighter on the team, and he’d be able to beat any of the ponies or villains easily… Until he gets hit with some illusion magic perhaps. Something that he’s had training against, but is still the most likely to fall for.  
Chiaoutzu is weaker than Yamcha, but being a spellcaster himself, he’d be even stronger against any magic attacks on him. There’s no contest. DBZ is simply always going to be in it’s own league.

Well duh. Sunset bailed on Celestia because she wanted to take the easy way out and just make Celestia give her alicorn magic because she decided she deserved it. Of course she wouldn’t be as strong as someone who actually studied and practiced magic.

@Tragiclady  
Applejack would be Yamacha, but under different standards.
 
Yamcha sucks, while Applejack gets bad screentime.
 
While he was kicking the Wolfmans ass, Applejack was kicking the Chimera’s.
 
I would guess Spike is Krillin.
 
Some of the MLP charaters could actually be stronger than the DBZ characters.

@The Smiling Pony  
Starlight seems to be more fond of doing obscure spells, so she’d have more practice doing the harder ones and can more easily output more magic, but if we measured Starlight and Twilight based on absolute maximum ability, I still think, simply because twilight has the connection of friendship, that she is stronger, she just doesn’t tap into that unless absolutely necessary.

I am actually upset

This is just the classic sensei and pupil syndrome. STARLIGHT PROBABLY TRAINED UNDER STARSWirl too.