It's difficult to really lay down a criteria for how to recommend this story. It's very popular, but I think it has a few caveats. The first thing that bears mentioning is that it gets off to a very slow start. The overall plot isn't so much "slow-cooking" as "it takes twenty chapters to show up." The first few chapters in particular are very slow, as they largely serve to introduce the setting and are pretty light on character interaction.
Basically, what I would say is this: read the first three or four chapters, and ask yourself two questions:
1. Do I find the protagonist, Littlepip, to be likable or interesting?
2. Do I like the action scenes?
If you answer both of these questions is "yes," then you can proceed without fear, because it is unlikely that the story will really put you off until its final act, which is honestly, apart from a decent climactic confrontation with the Big Bad
, an awful, awful mess.
If your answer to either or both of these questions is "no," however, that poses a problem. I answered "no."
If you don't like the action scenes, you're pretty screwed, as the story insists on resolving almost every conflict with them. It's one thing to overload the story with action, it's another thing when the action is completely boring, and there's only so many ways of saying "I shot him." More often than not, I found myself just skimming through the action scenes as they recounted Littlepip going through a succession of rooms, shooting everyone she hates, which she does quite a lot of.
I found Littlepip was kind of a dick. This isn't itself so much of a problem, but it makes me less inclined to care about her frequent bouts of angst, and I found it quite annoying how every character (including the token pseudo-pacifist) went on singing her praises. By the end of the story I found I had absolutely no reason to root for her.
The central party members who accompany her fare little better, as I found they were all unlikable in their own unique ways. The less said about Littlepip's love interest, the better.
That isn't to say everything is bad. The author has a nice flair for detail, the backstory is pretty well-crafted, and the blending of the two franchises is done in a way more crossover fics should strive for. Sadly, I just couldn't bring myself to care.