In recent years, Marvel and DC have realized that tying every book into a crossover often leaves fans embittered and angry (but hey, what doesn't?) so in an effort to reduce that, they've increasingly taken to that most frequently unsatisfying of beasts: the tie-in miniseries.
As such tie-ins go, "Secret Invasion: X-Men" has managed to hit just the right balance between stand-alone enjoyment, relevance to the crossover, and relevance to the wider arc of the X-Men. This issue sees the team successfully repel the Skrull invasion of San Francisco. Carey's wise decision not to do another Skrull-infiltration story gave the series a distinctive, militaristic feel, and that is ultimately reflected in the character material given to Cyclops in this issue.
Of course, the problem here is that previous issues focused not on Cyclops, but on Nightcrawler, who was wrestling against the brainwashing of a Skrull "bible" artifact. That plot thread is entirely absent from this issue, and instead Cyclops' decision to use the Legacy Virus against the Skrulls takes center stage. In fairness, it's a perfectly sound climax to the story, but as an issue, it's oddly out of step with what came before. The real surprise comes from Carey's resolution to the plot, as the Skrulls blow themselves up rather than surrender to the X-Men. Presumably, the plan was to get rid of what would otherwise be an inconvenient number of Skrull prisoners without the moral problems of having the X-Men actually kill them, but it's still a confusing moment that seems more driven by plot mechanics and necessities than by characterization.
The artwork from Cary Nord and Ma Sepulveda takes a bit of a downturn this issue, too. Nord's usually deliberate images seem comparatively wonky, and it all feels like somewhere along the line this issue had to be rushed through a little. Again, it's nothing overly poor, but after three quite enjoyable issues there's a noticeable drop in quality for the final part.
Still, as the definitive answer to what the X-Men were doing during Secret Invasion, it's ultimately a passable series that justifies its existence by filling its role in continuity. Not amazing, but if you want X-Men fighting Skrulls, then it'll do.