I enjoyed this more than 'The Avengers'
Why?
1 - I wasn't expecting anything. The Avengers is overhyped as this "epic" movie... PLEASE. LOL It's still just a silly popcorn flick where it is clearly "style over substance" - explosions, chases, one-liners over any sort of character development, except for maybe actors who care to bring it anyway even if it's not written (Robert Downey, Mark Ruffalo)
2 - The acting was way more relatable. Apart from Robert Downey Jr and Mark Rufallo, everybody's acting in Avengers is one-dimensional. Even the ones who in other movies can give out great performances, like Scarlett Johansson. Stiff and half-assing it...
3 - The special effects were in ENOUGH quantity. And CGI really well done. No flashy stuff coming at you constantly just for show. Smart!
4 - The concept was actually refreshing... the whole twist with the aliens being able to feed on electric power. Say what you will, you don't see those sort of alien creatures with those specificities in other movies. Unlike the Avengers' plot which we've seen in action/superhero movies over and over and over countless times, AND not even the aliens' looks were creative - same stereotypical "bad & ugly / disgusting" aliens Hollywood loves to fabricate.