I had an overnight CW flight from SIN to SYD, leaves 9PM, arrives 5AM, little time difference. You'd think it would be great.
Incessant yabbering from people sat next to me (not to mention the midnight-food service) meant I got about 3 hours sleep. Half as much as I got last week in WTP from NBO to LHR.
No kids in sight. I flew 110+ flights last year, in Y,W,J and F and never had a problem with children in any cabin.
SWMBO is trying to get us with 2y1m micro-wuk to go to Montreal this summer, rather than Helsinki and Tallinn. I'm still thinking about it, but we'll be in F or J if we do go.