This series has a clean, honest story line. It does have a traditional look about it, as someone mentioned, but that works for me. I'm a bit tired of the quick-cutting, montage-a-minute kind of film that passes for story these days.
The Hawthorne siblings are all different so you can find one to like and one to despise if that's your thing. Tessa is refreshingly naïve, a bit fruity, but I like Alison best, the cold, sophisticated one.
The other thing about this one is that it's not too freaky. I know it's fashionable to be pushing the envelope these days but I already think that sort of thing is done to the limit -- it seems like producers are going out of their way to find shock value. Sure, shock value gets people talking about your show but that's about it --- yada,yada,yada -- it's become boring, snore-producing.
Since I don't find much video/film/TV that impresses me anyway (compared to books where you can always find a good book), I like a good story with characters well-played even if fireworks and CGI aren't going on all the time.