Falling Skies is okay.  Not great science fiction, but good.  The special effects are convincing, but there isn’t much of it.  Most of the action takes place on a post-apocalyptic Earth.  I haven’t watch much of The Walking Dead, but it’s along that line.  The good guys are fighting the monsters in addition to a few bad guys.  The best thing about it is the series runs to completion, wrapping up the story.