I thought this episode was one of the best episodes Charmed has had in a while. Piper attacked Christy (the b**ch) so she wouldnt vanquish the Noxon demon that the Charmed ones were trying to interrogate. This caused Christy to convince Billie that the Charmed ones were just using her.
Billie is no longer on their side! I thought this main storyline was pivitol for the series and also very well done.
The other storylines weren't as interesting. Paige and Henry's storyline was the comedic relief and Phoebe's storyline was the love/shipper part.
Overall, if you like Charmed but have been disappointed in a few of the past episodes, this one is worth watching.