I gave it a 10... For me, it isn't as good as or better than, say, The Constant, Walkabout, The Brig, etc., but it's definitely in my top 10 favorite episodes. I agree, Time-Jumper outlined it great:
1. Loved scene with the smoke monster's perspective
2. Loved the cave of names
3. Loved the island boy
4. Loved the sideways Universe and all the intertwined lives of the Losties
5. Loved Sawyer's fearless character. I think he knows exactly what he's doing. He's playing the game.
6. Loved how Locke still seems to be a part of UnLocke.
7. Loved Ben's Eulogy for Locke - "...And I'm sorry I murdered him."
But to expand on that, I loved Locke in the flash-sideways. On-island, he was always the person saying that we've gotta have faith. Now, everyone else is telling him that: Jack, Helen, Hurley, Rose, Ben... and the only time he yelled "Don't tell me what I can't do!" is when he's Fake-Locke. It's as though, in timeline X, Locke is accepting his destiny, even though it's something he may not like, whereas in the original timeline, he's struggling to fulfill a destiny that he decided he wants but isn't necessarily his
actual destiny. I think he sums it up nicely when he says that a walkabout is "man versus nature", and he decided to stop fighting his nature.
I also like how we're getting flashes of Locke in MiB, but I really hope they don't make it seem like Locke's trapped in there, whole, and they can somehow help him overpower MiB to be alive again... ug, just writing that makes me a little queasy.