This show initially looked like a gritty, semi-realistic view of a civilization fighting for survival, but it turned out to be, IMO, a cliched hack job. It's not the worst thing on TV, but the list of things I dislike about it massively outweighs the points in favor of it.
Unlike most of the show's detractors, I have no problems with the set design and special effects, as I'm aware of the budgetary limitations that television has (especially basic cable) when compared with movies. I actually think these aspects are pretty good. My biggest complaints are about the actors/characters. I have never been a Noah Wylie fan, and I never will, and he, as a history teacher and weenie in general, is highly unconvincing as one of the best fighters in the makeshift military. Moon Bloodgood's character is vapid and annoying -- her entire race is fighting to stay alive, and she's bitching about LODGING ACCOMMODATIONS???? The military guy in charge is semi-interesting, but cliched. The bad-good guy (good-bad guy?) who is also a master chef is also semi-interesting, but I bet I could guess his story arc right now if I cared enough. The rest of the characters are as poorly-written as they come, and seem to act contrarily to how you would expect people to act in their situations. The only character I really like at all is Jessy Schram's, but she seemed (in the first three episodes, at least) to be a peripheral character -- one that I wanted to see more of, but instead got buffeted repeatedly with Noah Wylie and his annoying kids.
It is the basic cable equivalent of a popcorn movie, and that's not really my thing.