I'm a little confused as to what everyone is clamoring about. Was this episode a good episode? Yes. However, it was not fantastic and definitely not a series classic.
First off, the acting was phenomenal. I'll agree that Terry O'Quinn definitely nailed his part as John Locke. In most of his scenes you are totally invested in his character especially in the later scenes, but I'll get into that later. (Although, I would have like a little bit more emotion at the cemetary, but I think I'm just nitpicking now) While Mr. O'Quinn did a fantastic job, it was Michael Emerson who brought the episode home. While I'm on the subject of Ben, the only real standout scene in the episode was the dramatic scene between Locke and Ben. And the rest of the reviews on this site will reflect this. As the scene begins we see Locke preparing his suicide note; "Jack, I wish you would have believed me. Locke" But as John prepares to take the fall, Ben rushes in to save the day (or so we think). And Emerson (as well as O'Quinn)completely and entirely nails this scene. We are so ready and willing to believe that Ben has saved Locke that we are shocked and appalled when, out of nowhere, Ben violently strangles John with the extension cord Locke was about to hang himself. Aside from this, there weren't many other compelling scenes. Although, the Jack scene was pretty good too (mainly due to Mathew Fox.) Also I quite enjoyed the confusion that Charles Widmore and Ben have created. Just who is the bad guy? Although they had better answer it quick because if the producers keep rubbing our faces in it, it's gonna get old real quick.
A couple of the reviews on this site said that from watching this episode, we now know what Locke said to the oceanic 6. Well, I have a question to that. Who gives a rat's ass? Aside from Jack, the others didn't really matter. We already knew that Locke had talked to them and they had said they weren't going back, what he had said to most of them was irrelevant. It changed nothing! (Again aside from Jack.) I wish I cold have been as captivated as everyone else but the truth is, had it not been for the now infamous Ben-Locke scene, the episode would probably just be average.