I think it's still airing in the US, but aired in the fall in the UK; I watched it then. It's disappointing, but ends on a high note. And the Christmas episode was solid.
Ultimately I think the end of S3 really killed the show's long term potential, and it's now stuck with a variety of plots that are retreads. Specifically...
spoiler (click to show/hide)
Mary being courted again.
Still that storyline does introduce an interesting new character at least.
In short I don't think it'll ever return to the success of S1 or S3. Still, I really like the characters, and S4 has multiple great moments that made me smile. At this point I watch the show mainly for that stuff.
