The show has its moments. But they're very few and far between. The pilot was generally excellent, and the very end of this season's mid-season finale was pretty strong. In between? Mehhhhhhhhhhhh...
The show had its budget slashed brutally between S1 and S2 and it shows. There are very few "zombie" moments, and where there are you seldom see more than a small handful at a time. The vast majority of the show is therefore given over to the human cast. This is fine, really, to make this a human drama instead of a zombie action show, but it's not a very GOOD human drama. The acting is spotty, the characterization ranges from bland to annoying, the lead is an unbelievable Mary Sue, the conflicts are tedious and poorly delivered, the show lacks tension and pacing, the writing is all over the place, and perhaps most unforgivably there is little to no air of threat.
By the standards of most television, it's a decent enough show. By the standards of GOOD television, it's actually pretty bad, and I'm rapidly losing patience with it. I guess it depends on where your standards are.