The first two seasons were good. The last season was garbage, not because of the change in cast (sad to see the guy go, glad to see the girl go), but because he producer's went out of their way to make the episodes more like mini horror movies which is not what the show is about.
Also, the arrogance of Megan Hunt was a turnoff throughout the run of the series. Like, it was too much and I disliked her more and more.