I watched it and enjoyed it. Remember, a pilot is supposed to introduce the characters and setup the premise of the show. Mission accomplished. We know who our heroes are, we know who the villains are (mostly), we know the parameters in which they'll have to work, and we know what they want to accomplish within the season(food and weapons, free Ben (the harnessed son), and take down the alien tower.
This isn't a movie with a 100m budget. It's a TV show. If they tried to show the invasion on a shoe-string budget, everyone would be carping about the bad CGI.
Unless the show takes a dive over the next few weeks, I'll be tuning in faithfully.