Outbound my preference is sleep and ease of getting access. For NYC-LON I would take the often past midnight BA option.

Inbound I focus on impact of adapting back to my standard time zone. ICN-JFK was a day flight where I landed and was back home and into the office by noon or able to push through the day after just a little napping on the 14 hour flight and then crashing for some solid sleep.

Another deciding factor is the airline & plane. I would not want to be in a generally poorer J hard product product (such as BA) with poor entertainment and a poor soft product/food service (something I found BA can do well) for a long daytime flight. If the product is lacking at least I can just sleep as much as possible.