This is a somewhat seminal episode as the series says goodbye to Belthazor and Cole becomes temporarily mortal.
There are a lot of good elements and scenes in this episode. Phoebe and Cole have some excellent scenes together, including the scene where Cole convinces Phoebe to get his vanquishing potion and their penultimate scene up in the attic. Sykes as Belthazor's protege is fairly effective, though I think a younger man might have made a better protege. It is a little odd seeing two demons fight it out like gorillas instead of using their powers, but the huge actors did add an epic dimension to their clashes. The vengeful woman, I thought, was a little overplayed and somewhat annoying. Her obsession made her a very unsympathetic character, and it was a little disappointing that the sisters wouldn't defend Cole with a little more vigor. After all, how many times has he saved their lives now? I understand now that the writers were continuing to set up Paige as the anti-Cole, which gives us the epic pay off in Centennial Charmed, but Cole even saved her life when Shax was after her. Maybe she should remember that.
On the other hand, I do admit this plot line does bring up a very confounding moral dilemma for the sisters. Yes, Cole is helping them now, and he has saved their lives. However, does that balance over 100 years of committing evil acts? Impossible to say. It seems to depend on what side of the ledger you are on. For the Charmed Ones, absolutely Cole has been a powerful ally that they should defend for their own well-being. However, for the woman who lost her loved one to Belthazor, there likely is no act that would redeem him. The ending gave us a rather convenient solution to the dilemma. The woman gets her revenge on Belthazor while the Charmed Ones get to keep Cole around. I initially thought it was a terrible idea to strip Cole of his powers. Fortunately, that condition doesn't last for long.
Strong and important episode as Season 4 maintains its high quality.