Torchwood: Miracle Day is out on DVD and Bluray in the UK today,
read Blogtor's review HERE. There are only two audio commentaries on the set, so you may want to revisit the episodes with the "informed" commentaries from
Blogtor Who. Included below are links to each audio commentary from the series. Be warned, however. Some of the commentaries match the more "adult" tone of the episodes.
Visit the Miracle Day section HERE.