I thought this was a good solid start to the series with an interesting new villain set up for further appearances. The show felt like it's being pitched somewhere between SJA and Torchwood, though with a gore content at least as high as Torchwood.
My main criticism is that the premise feels a little too close to that of Torchwood: a location with a rift though which the weekly threat can emerge.
I was really enjoying it until The Doctor showed up. I think it was too early to work him in, and he was a bit too much of a magic "fix everything" button. If they had held off and worked him in in a later episode, and had him join the team when they have a bit more experience and are on more equal footing with him, then it would have been much more interesting.
It was a stronger start than Torchwood had though, and that got really good over time, so I'm feeling positive.