S&S has the best selection Ive seen so far (ive done LL, CD, Exante) and its more flexible than some and cheaper.
I would add more protein and veg to your day if you're concerned about the calories being too low, but it best to start off low then gradually add more.
Cambridge have a few programmes too, so if you needed more guidance then they would be a better option. Saying that S&S offer great online support from their website