A classic X-Men crossover done completely right!
For me, the X-Men books are at their best when they're steeped in huge, overarching stories with big themes and big action. It's what I grew up on and it's what I get excited for when I pickup an X-book. Now, that said, I do not expect these type of stories all the time; rather, I prefer for them to be the culmination of a few years of slow-burn story. And this is exactly what Messiah CompleX is, and it does it so well.
I recently reread Messiah CompleX in trade form--it's my third overall reading, the first being via single issues when they came out and the second being a collective reading a few months after the event finished. Upon this third reading I found myself enjoying the story more than I did even the first couple of times, and I loved it then.
As a disclaimer, I think MC is best enjoyed directly after reading Blinded By the Light and maybe even Supernovas. This is, of course, assuming you've read Decimation or are at least familiar with what happened. This goes back to what I said in the very beginning about the X-overs working best as the pinnacle of a long series of stories.
The story is so, so good. I just want to state that outright. Honestly, what makes the story so amazing is the pacing--the writers came together (amazingly!) to craft a story with a huge cast of characters and a multitude of inter-weaving plot threads and they do it at the perfect pace. Nothing feels rushed except for maybe the very last moments of the last act (more on this later...), and the overall story feels like it moves in a natural direction.
The overall driving force in the plot is simple: an important baby is born and many factions want control of her. That's it. Now, years later we know who this child is and just how important she is. However, I remember reading the single issues as the were coming out and constantly trying to figure out who she was or why she was so important. You lose this charm reading the story now, but even better is the fact that there are so many little nuggets and allusions in this story that are picked up on in retrospect.
What's really special about the story is all the little plot threads and character beats that come together to shape and augment the main plotline. Almost every character feels fully developed and totally motivated to do what they're doing. It's hard for the reader to grab onto just one character's logic and say "this is who is right here" because almost all of them are acting completely within the reason--even the villains.
And, I have to stress that, in retrospect, MC sets up so many character arcs that would come to define a huge number of characters in the years following its completion, all the way up to present day. There are so many characters that I can go into (PM me if you want to chat! ;) ), but I'll only focus on a few here.
I especially loved rereading the formation of X-Force. Seeing Scott make that decision and Logan's willingness to execute those orders makes so much sense now, but I remember reading it originally and feeling the gravitas of the situation from that moment. Watching X-23 be so vicious and so effective, Logan literally tearing sh*t up (as he always should!), and Warpath feeling awkward about his new role as a killer and coming into his own is all amazing.
Gambit and Mystique really shine as well, and you get to see the full range of development happen for these characters and their relationship to Rogue. It's amazing to me that Rogue spends the great majority of this story off-panel and in a coma, yet her character is developed through Remy and Mystique. You get to see Gambit as the true wildcard that he is and Mystique in all her tortured, tragic and demented glory.
The last set of characters that I want to talk about here is Cable, Bishop and Cyclops. These three are the major actors in the main story, and all three are operating under their own vision, which is so, so important to the progression of the story. Again, the writers use other characters--Madrox and Layla--to develop Bishop's story and why he's doing what he is. It's an incredible framing device and it doesn't allow you to write Bishop off as a lunatic, because you are forced to understand where he's coming from through the eyes of Madrox and Layla. At the same time you get Cable, representing the polar opposite of Bishop. Cable just works as the outsider antihero and when you see him for the first time in MC, you know the story is about to pickup. His views on the matter are so poignant and so reasonable that you, again, cannot say he's unjustified in his actions, even as they lead to our protagonists taking casualties.
If Decimation was the story that set the status quo for mutants as a group, then MC is the one that set that course for Scott Summers. This is where Scott becomes the leader of X-Men in totality. He pushes Xavier aside for the greater good and he makes the hard calls that he knows are necessary not for himself, nor for the X-Men, but for mutantkind. MC brings Scott's character to a new level, and rounds him off a bit in that you get the sense that he's now come full circle, and will thrive as a leader, if even he will operate outside of Xavier's vision.
I said above that there were a few pages that I thought felt rushed, and unfortunately, they come at the very end. The last few pages wherein Cable is given the child and Xavier is shot in the head come off as an abrupt conclusion to such a long form story. This may be what the writers were going for, but it still kind of comes off as hasty and haphazard. I think it's also worth considering that there are stories collected in other editions that follow this conclusion and pick it up and run with it, so it's not a total loss in a conclusion.
If there is one aspect to MC that isn't completely amazing, it's the fact that the art changes so frequently as the story jumps from issue to issue. I don't necessarily have any real problem with it, but I know this really trips some readers up. Stylistically, the many artists are so different, so it's really jarring, but I don't think it's enough to detract from the overall story.
I will say this: when I think about MC I think about it being drawn by Bachalo and Ramos. It may be because the majority of the battles and action sequences fall into the books that these two were tasked with drawing, or it may be because I prefer their highly stylized art over the others working on the story... I'm not entirely sure. I just know that, in my head, I remember the events of MC as told by Bachalo and Ramos.
It should be clear by now that I recommend this book to any X-fan. This, to me, is a five-star perfect-as-it-gets X-Men crossover story. As far as characters go, there's enough for every fan--i.e., if you're a Cyclops fan this story is for you, if you're a Wolverine (and X-Force) fan, or a Gambit fan, Cable fan, Bishop fan, or even a fan of the Marauders, this story is for you, ad infinitum. But what really makes this story so perfect is that, thematically and tonally, it represents the essence of the X-Men. It's mutants fighting against all odds, on all fronts, facing insurmountably grave conditions. It's characters that we love being developed and matured, cultivated into who we know them as today.
This is an amazing book, and if you're a true X-fan, you'll love it. I cannot see how this story won't make the top 10 story list of X-fans everywhere. Do yourself a favor, pick up the paperback, sit down for a day and read through it. You will not regret it.