This episode blew me away, and not because it was so action packed or full of reveals. It blew me away because it brought back the essence of "old" Lost... the character and amazing dialog that defied the first 2 seasons.
I'm glad the writers chose this approach over the "boom boom bang bang" one, which I feared would happen given how fast paced the show has become.
This episode was a joy. Yes, there are seemingly weird stuff in it(suddenly everyone appearing on the plane), but hello... this is Lost. We'll get flashbacks, I'm very sure about that.
Overall I think 316 is on level with "This Place is Death", but is brilliant for different reasons.