It was a very confusing episode, but what I got from it through "plot device reborn-Charlie" and "plot device reborn-Daniel" and "all-knowing Eloise" was that this alternate world is a place where everybody gets to have their (almost) biggest wish come true (Desmond being accepted by Widmore, Nadia alive, Claire raising Aaron (Kate and Claire's wish), Jack's son, Alex alive (Ben's wish), Miles living with dad, Charlotte alive and musician-Faraday, lucky Hurley, Sun and Jin running away together without Sun's affair, etc. (not sure about Sawyer though, maybe Juliet alive and not-killing-fake-Sawyer?). And this seems to point out that the ATL is the result of MIB's promises (he did promise Nadia to Sayid), so as me and some other folks were saying for a couple of weeks now, MIB apparently won the battle, killed Jacob for good, sunk the island and gave everyone a second chance to live out their dreams without Jacob ever interfering.
BUT
Apparently, some people believe that this new reality is PHONEY. Charlie wants to die so he can be in the other timeline with Claire, not knowing that he died there. Desmond seems to want to get back to the timeline where he and Penny have a child, because he feels that the new reality is fake, and probably most of them feel the same. So the show could end by them all meeting (since Desmond will try to bring them together) and merging the two realities back into the original one. But that doesn't make any sense, since most or them are DEAD or MOURNING their dead in this bloody timeline. They would be better off trying to live their best in the ATL (Sawyer finding Juliet, Des marrying Penny and having Charlie, Daniel fulfilling his love for Charlotte etc). So why would they go back, unless it is a necessary sacrifice to, ahem, save the world (cough). Maybe MIB is free in the ATL and the evil starts spreading, and they will stop it, but the whole cork thing makes no sense to me since the world is already a frakked up place.
In conclusion, I think that MIB initially wins, creates the ATL, but memories from the OTL slip into our losties minds and make them want to reject ATL, return to OTL and re-insert the cork, once again trapping Smokey, as Jack/Hurley/Sun/Kate becomes the new Jacob and history loops once again. But I still see no immediate reason to reject ATL, just because "it doesn't feel right". If you had a chance to be with your loved one (after a supposed deal with the devil), wouldn't you chose to? And what would change your mind except for the threat of Armageddon?
