Yesterday the first episode of Miracle Day, titled The New World, was broadcast in a special BFI press screening in London. Naturally, a couple of sci-fi sites attended and have posted their thoughts on The New World:
http://www.denofgeek.com/television/947521/torchwood_miracle_day_episode_1_spoilerfree_review_the_new_world.html- Den of Geek's review
http://www.sfx.co.uk/2011/06/21/torchwood-miracle-day-episode-one-spoiler-free-review/- SFX's review
As you can see from the reviews, the reception has been very positive, especially Den of Geek's, saying that it's up to the standards of Children of Earth!