I am surprised and thrilled to report that I actually really enjoyed a Marvel crossover! The first one in years! Now, I don't think this comes anywhere close to the narrative force of something like House of M or the scope and plotting of something like Infinity Gauntlet, but I was very happy with this. 
 The opening is a little concerning. The Avengers learn that the Phoenix Force is returning to earth, likely to inhabit Hope, who's been built up as the mutant messiah for a couple of years now. So they confront the X-Men about this, of course. What follows is a very dumb fight that just reads like a bunch of nerds in a comic shop talking about "who would win, Magneto or Iron Man?" "Duh, Magneto, bro." "Yeah but what if Iron Man changed the polarity of his suit?!" "Durrrrr I don't know." Also, at this point, the X-Men are very clearly the bad guys, with no moral leg to stand on, which makes you solely root for the Avengers. Luckily, this kind of nonsense goes out the window pretty fast in favor of a much richer story. 
 I will say, like most crossovers, this is pretty much all plot. There are so many characters and so much going on that they can't really stop for much character development (this probably happens in the supplemental stories in other books). But for a slam-bang action fest, this really works. The stakes continue to heighten throughout, it becomes less clear who's right and who's wrong, and things genuinely seem pretty dire for several of our heroes over the course of the story. Also, in these big crossovers, anyone's fair game to die, so that fact adds to the tension here. I found myself flying through this much faster than, say Fear Itself or Siege (two recent events that were pretty lackluster overall), excited to see where the story took me. You could do way worse than this, in terms of major comics events! And hey, maybe that doesn't sound like high praise, but I'll take what I can get.