In my pithy summary, I said the two best things about this episode: the sexy Rebecca Cross as Charlene, and the touching scene where Leo's future wife meets his past wife.
This is a nearly unique episode in the fact that all three sisters have their own thread with virtually equal time being spent on all three. Phoebe's story is the only supernatural one of the three. It is an up and down subplot. Rebecca Cross belongs on my list of hottest actors to ever guest star on Charmed. The idea of a Libris, and Prue astral projecting in to vanquish him was excellent.
Unfortunately, this subplot would have been better with more time devoted to it. Libris, I think, had the shortest stint for a demon ever. Plus, the explanation of Charlene being killed because why? She was going to prove the existence of demons through reading books? Craziness. Prue's storyline is probably the weakest of the three. This episode again brings up Prue's issues with Dad, and his birthday kind of lingers in the background. Though they address it directly with the conversation with Phoebe, I still don't see how ultimately they weren't punishing the guilty in this subplot. The entire confession scene was beyond contrived, but I guess it managed to wrap up two plotlines in a succinct manner.
Piper's subplot is the strongest part throughout, starting with their date; Piper looked great, and it is always cool to see them orb together again. Even though the fight scene was preposterous, why would Leo and Dan be fighting again?, Dan being set up in conflict with Leo adds something to the last couple episodes of the season. Easily the best moment of the episode is the well-written scene where Piper meets Leo's past wife. That scene reassures Piper and the audience of who Leo is/was. Like pretty much all the episodes down the stretch for Season 2, this is a good, not a great, episode.