I also enjoy, still, how Shepard plots. Her plotting is tight, and you can tell there aren't any extraneous scenes. Unlike some authors, she doesn't put random sexy times or kissy times to please the fans that like that kind of stuff. She does things that are necessary only; she doesn't write filler books, which makes me glad.
There's nothing I dislike more than an author who adds books on to a series just for length and fan appeal and money *coughcough* BECCA FITZPATRICK *cough* (C'mon! You ALL know Silence wasn't necessary.)
Besides Emma and Sutton, the characters thrive. I can't help but compare them to the TV show. I'm really glad the TV show didn't make everything the same. In the books, Ethan is a total dweeb/nerd/dork and Thayer is the ultimate bad-boy eye candy. In the TV show, it's reversed, which might seem odd to some, but it works.
There's also another key aspect of the TV show that's different. Sutton's actually alive in the TV show. They're not trying to find out who killed Sutton, since Sutton isn't dead, but rather trying to find out who their birth mother is. The TV show is filled with so many wicked cliffhangers at the end of episodes, but unlike with the books, you only have to wait a week, as opposed to a half of a year, or more.