There's not much to say about X-Men: Apocalypse other than if you like
the X-Men, you'll probably like it. The action looks cool, the plot is
interesting (albeit simple), and you get to see more characters in their
younger iterations.
I begin this post about X-Men: Apocalypse with the disclaimer that I've never seen an X-Men movie I didn't like – although that could be because I've strategically avoided X2 and X3. And I knew I didn't want to see The Wolverine. And it's not even listed as an X-Men movie, so I'm not counting it (I didn't like it. But I did like X-Men Origins: Wolverine, unlike everyone else). I watched and liked the animated series, and the X-Men are definitely my favorite superheroes.
Apocalypse got a lot of bad reviews. It seemed like no one really liked it. I liked it. I didn't think it had too many characters or anything. A lot of them were people we already knew. I can't stand Sansa as Jean, though. I just don't like that actress. Then again, I felt the same way about Jennifer Lawrence, and I'm getting more used to her in the role now I guess.