Generally, viewers require an awesome-looking alien, a valid purpose for its motives, and a clearly defined villain. I thought the alien looked awesome—a little bit like a Decepticon from Transformers 2, but still awesome, especially when it crept up on you before it attacked like the creatures in Alien and Jurassic Park. My movie buddy pointed out something interesting. Director and writer J.J. Abrams clearly has a thing for unseen monsters that make rattle sounds and have underground lairs, which he made good use of in ABC's "Lost."
The alien's backstory was E.T.-like and even Paul-like, being stranded on Earth, hunted down by government agents, and longing to go home. Of course it wasn't as friendly as either of those aliens. It was a lot more proactive and learned from imprisonment not to rely on any human. I liked that it spoke through touch, but we didn't hear it—just like the Black Smoke. And I loved its spaceship, which broke up into tiny Rubiks cube sized squares as a defense mechanism—a novelty item that was designed in '74. And his method for collecting them was genius. His intelligence and advanced technology almost has me worried that he might return with an army to seek revenge. The real villain though was the army that imprisoned him and anyone that helped him. It would seem that in the 70s, the army was often the enemy, infringing on civil rights because of the heightened security during the Cold War and fear of the Russians.
Overall, I would definitely recommend seeing Super 8 for the action, the acting, and the alien. But I give you two points of advice:
1) Try to see it with captions—that's actually an option in some theaters—to catch the funny off-camera one-liners and
2) stay for the credits to watch the kids' final product. You'll feel as though you made it with them.