Obviously, the graphics and scenery are really well done, as one would expect from all the hype surrounding the large-budget production. The dinosaurs are better than anything I've seen on television, and I admire the care and planning that has been put into the futuristic trappings.
The cast and characters are generally well-done. Jason O'Mara and Shelley Conn have great chemistry and I have enjoyed watching their characters rekindle their relationship. I will agree that two of the children: the youngest daughter and the eldest son, are grating and pointless. The daughter seems to mainly have existed as a plot point in the pilot: to give the family a reason to escape to Terra Nova and ratchet up the stakes while still building sympathy for the parents. After that, she's just too cutesy-wootsy and tends to get in the way. The son is the dreaded "worst offender" of the show. I think that probably without him, a lot more people wouldn't have so much to complain about. Every single storyline for him is a mess of clichés, from "son is inexplicably always angry with father" to "son is horny and will do stupid things for a hot chick" to "son is a moron and really deserves to die, but he is a main character, so we will kill someone else to teach him a Very Important Lesson." The middle daughter is much more tolerable and her storyline is (dare I say it?) sweet. In that manner, I find it kind of refreshing to mash up family-friendliness with sci-fi stuff. How often in dinosaur flicks do you get to have "sweet" (not ooky-gooky, just tender) moments between characters? Not that often. Stephen Lang and Christine Adams as opposing leaders of Terra Nova and the Sixers are probably the strongest performers of the lot.
Overall, the stories have been pretty good, and never what I would consider to be offensively unwatchable. It's not LOST, but geeze, why should anything else try to be LOST? LOST was LOST and this is Terra Nova, and it is good at what it is. It's interesting and exciting and entertaining. The b-plots can tread on tired ground, as I have mentioned above, but the a-plots are solid.
Overall, Terra Nova does what it aims to do well. Sort of a loose contemporary spin on Lost in Space, but with dinosaurs. If you don't like those kinds of shows, guess what? You won't like this. And that's okay, but that doesn't mean that Terra Nova is badly done by any means.