The first series of this Dr. Who-spin-off has been quite childlike in many ways - apart from the "historical" background of the main-character. This series now is more adult in its tone - perhaps because the prospective viewership has gotten one year older ;-).
After Maria has gone to the USA with her Dad a new family moves into the house opposite Bannermann Road 13 and the daughter of the house - Rani - would like to become a journalist, which makes her a shoo-in as Maria's successor. And so in the first episode, where we meet a Sontaran, she quickly learns about Sarah Jane and her little "boy-group".
The episodes are again very emotional, as we a used to from "Dr. Who" and "The Day of the Clown" has some very nice hints into the direction of Stephen King's "It". In "Secrets of the Stars" the Zodiac becomes an important factor of the story and in "Mark of the Berserker" we get to know Clyde's father - and more importantly, his mother. In "The Temptation of Sarah Jane Smith" the Trickster lets the heroine meet her parents and puts a difficult choice in front of her. The final episode "Enemy of the Bane" lets the villains of the very first episode of the first series return.(And parenthood again becomes a topic).
All the stories are quite well written and the effects a not as cheesy as they have been sometimes in the first series. So this is well.
In the extras we find character-, villains- and tools-profiles, whereby one such list on one DVD would have been quite sufficient. There are written summaries of the first and the second series, interviews from Blue Peter with the younger part of the cast, a very nice trailer, audio clips, a photo gallery, short films with Tommy Knight and the sound-man (which I didn't really need) and a short Comic Relief Special for 2009. All very lovingly done if not really always interesting.
All in all - and for the important part, namely the episodes - a very nice collection.