I enjoyed this episode. Sure, it wasn't fantastic, but it provided enough interest in terms of Walt/Michael along with the rest of the intricacies.
The ending was a bit of a surprise, but I could tell it was coming, what with the rather large emphasis on Charlie/Claire all of a sudden. Still...one has to wonder just what is going on.
And, don't expect the "Back Story" to end any time soon, folks. I know that Sawyer has another episode upcoming, so if I were you I'd get used to it. I find them to be interesting in terms of why they're there. Really, if it was just about some crazy island, I think it would lose an element of interest. Sure, if you're looking for a pure mystery show, the characters get in the way, but if I don't wonder about these people or feel like they're not just one-dimensional characters, there has to be something. With a smaller cast, their interactions with one another do this. In such a large cast, it doesn't work that way, so the inclusion of the back story is used. And it works.
A lot of shows are going on hiatus this week until Feb. Sweeps.