Contains spoilers, totally and completely. I mean, it's the internet.
I caught both recently on Virgin Atlantic. The screen was a little small and glossy so had lots of reflections, which did not do well by Ex Machina but Chappie does fine with it. (I think a better title for Chappie would have been Scout 22, since "chappie" makes little sense in American English.)
Both, by the way, are recent movies about AI, yet they are very different.
Ex Machina has a few characters, few speaking parts, and is sparsely beautiful (best watched on a big hi-def screen).
Chappie has lots of speaking parts, and is familiar to viewers of Blomkamp's film District 9 in terms of the visuals -- a rough, decaying world in South Africa with lots of little details, because when things fall apart or get blown up there are lots of little bits.
In this, they are opposites. They are also opposites in how they treat AI -- in Ex Machina, the AI is software and hardware (the cool glassy blue brain objects), and the objective is humanity -- they have human faces, bodies, and can make and read human facial expressions. In Chappie, the AI is in a somewhat clunky-looking (but adroit) robot body, and the AI is the software (it can survive in a USB dongle).
For Ex Machina, the point is for the AI (and its body) to become human.
In Chappie, human consciousness can be scanned and downloaded into the robots (no special brain neeeded, although the robots have good brains -- this is science fiction, after all).
So AI/robots becoming human, and humans becoming robots.
Yet they share the same approach to the creator, a male genius who is the solo creator, more or less of a loner (it varies in the two films).
In Ex Machina, the AI/robot seeks to hide in humanity and does not trust them (well not the initial human characters) and kills her creator (although the creator is horribly abusive and ego-maniacal), whereas in Chappie, we know they become known more widely to humanity and Chappie (the AI in the film) trusts the humans he comes to know and helps save one of them, the AI creator.
Ok I don't really have anything deep to say, but they are both pretty good. In Ex Machina I think the two main male characters aren't written as well as they should be, they are a little overdone and tedious at times, but in Chappie I really liked the characters, and Die Atwoord are great. Ex Machina would have benefitted from a better, bigger screen. I also thought the music in Chappie was really good. I also thought Alicia Vikander's performance was great as the main AI in Ex Machina.
Apparently I disagree with reviewers on all this.