Smallville Episode Review: "Persona"

As mentioned in the "Recap" post, I'm trying something different. This, instead of a play-by-play, will sum up this week's episode without too many spoilers.

The episode tonight was incredibly intense. As you may or may not be able to recall, the last episode ended with Kara missing, a problem in Lex's lab, Lex revealing that his dead baby brother, Julien, was alive, and Jar-El, Clark's birth father, telling Clark that he's messed things up for the last time.

Turns out, Jar-El, instead of killing someone close to Clark has simply been holding him for the time being. Meanwhile, a Phantom Clark-look-alike has taken Clark's place and moved into his life. The problem? Other than the fact that our hero is in deep trouble: no one's realized.

For the Clark phantom, there's another problem: the yellow sun of our world turns his skin to stone. He needs to try to figure out a way to make that stop, realizing that sooner or later, someone's going to catch on. And it's just a matter of time before someone does.

This episode was intriguing, and it raises lots of questions:
How much longer before something happens to make Lana and Clark break it off for good? Their relationship isn't the best at the end of this episode: to put it lightly. Which would you choose, though: a man who says he loves you but is never there, or someone impersonating him who would turn over the world for you?
When will they find Kara? Is her memory going to return?
How will Professor Fine's finding information about himself affect Clark (read the recap) and the others?
How will Lex handle the situation with his brother? Does it help shape who he becomes?