I was on it ORD-SFO on Sunday.

Hadn't been following this thread, so didn't even realize anything had changed until I got onboard and said 'this looks different'

First impressions: J looks perfectly fine. Yes it's 2-4-2, but the seats are lie flat; the screens are big, etc. it's no Polaris, but for the largely domestic runs it will be fine.

Y is NARROW. No worse than the 787 I was on last week, but man... That could be rough on a long flight. Seats were fairly firm. Power outlets are on the seat in front... No scrounging underneath your seat trying to find it. They have this new blue light that shows up in the aisle when people were plugged in, so FAs can easily enforce the nothing plugged in at takeoff rule. Boo. Overhead light and FA call button was in the top of the armrest, which is the only major design flaw. People were constantly pressing the button while just resting their arm on the armrest.

The neatest thing in Y is the iPad holder mounted in the back of the seat in front of you ( where the IFE used to be ). I know there's mixed feelings about no IFE, but I personally think it's pretty genius.

Wifi didn't work, which I wasn't happy about ( but they gave me a $200 ETC as compensation ).

All told, a fine config for domestic, minus the horribly narrow Y seats.