[spoiler:3oz5ebkr]This was a decent episode. The main problem for me is that I'm not all that interested in Kate or Claire anymore. They've both run their course. The Claire reveal at the end wasn't really surprising at all, apart from the fact that it muddies the waters of the Danielle character in ways I don't particularly like, like suggesting she was infected. Which I firmly believe she wasn't, considering she killed her friends to avoid it and stayed in a small shack rigged with explosives (which, surprisingly, seem to work on Smokey; I think this is significant for my argument that Danielle was not infected). If they're trying to say she was infected, then I think that's pretty bad retconning of events, unless they come up with a really good explanation as to why. Another reason the Claire reveal didn't surprise me is that it was pretty much revealed to us in season 5 that Esau used Christian Shepherd's body. The larger ramifications is of course that Locke was tricked by him at least twice in previous seasons, and - and this is something we probably shouldn't pay much heed to - helped Jack find Adam and Eve and the caves in season 1.
I agree that Sayid's infection must be the same as Rousseau's team. I think a contender for the moment of infection is the actual spring. The water wasn't clear, as it seems Lennon and Dogen was used to, and Dogen had probably revived people with the spring before, and yet this time he genuinely believed that Sayid was dead. It makes no sense to me that Esau would want Ben dead through Sayid, since that would undermine his proven abilities to plan ahead. I.e. since his was a long con, I wouldn't expect him to try to kill a man he later uses for an important purpose. IMO Sayid acted on his own back then, suggesting that the infection is recent.
Before the season started, I was convinced that Jacob was the bad guy, and that Esau/the nemesis was actually the good guy. It seems to me that Jacob's goodness is inscrutable at best. He not only stood by watching Nadia's death, but he actively participated. He seems to bring people to the island at all costs, killing is no obstacle. His attitude towards Ben is indefensible, even if Ben's a son of a bitch.
Even after it's been established that Esau and Smokey is the same guy, it's obviously not as Jacob-good, Esau-bad clear-cut as some people like to think. Jacob sure as hell isn't a very NICE deity. Richard (through Jacob) didn't object to the Dharma purge, for one thing, and Jacob's cavalier attitude towards letting innocent people die has been well documented. It'll be interesting where this is headed.
PS: The bully with the other-others wore red pants! That made me laugh. It must be a Star Trek/redshirts reference, no?
PPS: ETHAN RETURNS!! He was - hands down - the best part of the episode. Man, that guy is creepy. I watched "One of Us" (ep. 3x16) this week, the one where Ethan and Richard take Juliet to the island. Great stuff. Ethan = Best villain ever.
PPPS: Jack annoys me too, but he's needed the way he is. He needs to doubt the faint smell of mumbo-jumbo. Remember how he doubted weirdness about the island even AFTER seeing the smoke monster? This is like that, and it's needed so the show doesn't spin completely out of orbit.[/spoiler:3oz5ebkr]