In my humble opinion The Constant, season 4 5th episode, is by far the best Lost episode. In fact it's the only one I rated 10 out of 10 with Sundown. So at the end of The Package when Sayid and us saw Desmond my heartbeat went on a tribal rate that lasted until now. One week to remember what happened. One week to think about him and Penny. One week to feel in love, again.
Happily Ever After wasn't as strange as The Constant but it was definitely an excellent installment. First Henry Ian Cusick's performance was impressive and his charisma astounding. Considering his appearances are rare comparing him to Matthew Fox wouldn't be appropriate but they definitely play in the same league, right with Terry O'Quinn and a few others. Second watching the episode was as intense as riding a twirling roller coaster. From the characters he met to the alternative situations my jaw was sweeping most of the time. Third even if I found the story a bit naive, probably because I'm not obsessed by romance, it was quite inspiring.
But I can't help thinking that it could have been better, even if its forty minutes felt like seconds. I found the island and urban arcs weren't well balanced and the transitions between the two not as creative as in Dr. Linus for example. An other issue is that Desmond hadn't been featured a single second since LA X and it was already ten episodes ago ! So I think his coming back should have been better planned, with some sort of prequel episode or something. Moreover even if some moments were intense it didn't reach The Constant's level, far from it.
Last but not least the most disappointing element was probably the pace. It's like nothing much happened. I think some parts could have been shortened to give some space to more important ones. The first half wasn't that surprising for example when the other one was astonishing. But don't get me wrong the last seconds confirmed that the remaining episodes should be captivating. Considered as a standalone episode Happily Ever After was just great but if you try to comprehend it as a whole then it could be the gear wheel that controls them all. A first step toward the inevitable end of Lost.