Well, first, they promoted it to BBC1, which may or may not be a bad idea for a mediocre little Doctor Who spin-off that started out on digital TV a couple of years ago.
Second, they cut the series length from 13 episodes to 5, making up one big story (like they used to with Doctor Who - complete with cliffhangers!). It remains to be seen whether the story has the legs for a five-hour mini-series, but so far it's nice to have the cliffhangers back.
The they put the whole thing out on consecutive nights, because of course sci-fi fans don't go out of an evening. Interesting choice, but in these days of Sky+ boxes, largely irrelevant (provided you can avoid reading spoilers on twinternet).
And then, just to top it all off, they went and made it good. I mean, witty one-liners, fast paced action, intrigue, mad plot twists and even madder telehandler-based scenes... this isn't the Torchwood we all know and, um.. go 'meh' about, is it? Admittedly there has been some brief nudity and Ianto's wierdness about being a couple with Jack, but on the whole everybody's libido seems to have been turned down to a more sensible level. In such a world, almost anything can happen... although, I have to admit, the extent of Jack's immortality is beginning to stretch credibility somewhat.
I'm not going to go into more detail than that; there will be plenty of reviews online if you need one. All I'm saying is that on the whole, I was pleasantly surprised. If you'd written Torchwood off as a waste of valuable TV time, it might be time to give it another chance.