To answer my own question, 40AB has excellent legroom. Flew HKG-ORD Able to stretch out and touch the wall with your toes if you try, but plenty of room to get out for walk/toilet visits, without bothering 40C.
My experience--
Was greeted by 2 FAs as a OWE, friendly enough. Meals were out of choices when they got to me in the first row of Y (guess they serve from the back?). Bathrooms filthy by end of flight.
Comparison--just one example, one flight each way--
Comparison of HKG-ORD on CX to SFO-SIN on SQ last week-- CX first meal was better than SQ. SQ bathrooms much, much cleaner, both on 15 hour plus flights.
Service on both was excellent! CX First Class Lounge (The Pier) was absolutely fantastic. SQ had no status, so no comparison there.