In my experience: NZ > AC > LH

NZ has standout seats and food. AC and LH have roughly comparable seats but AC offers a main meal that is better than LH (who just serve the Y meal on upgraded china).

I do think it is a good mid-point between J and Y with more comfortable seating and somewhat enhanced service. AC's PE experience is also better on 787 and 330 than 777 due to ability to access a lav up front.

Agree with [MENTION=817598]songsc[/MENTION] that the product isn't as good on AC as it was when first introduced when there was a curtain dividing PE from Y and the meals were a reduced selection of the same main course as J.