Originally Posted by
Flyer_70
Am I the only one here that would think long and hard about this? Unless I was stuck in the middle of E- on a sold out flight, I could probably deal with 6 hours in Y. I have better things to spend $400-$500 on and I don't see me feeling that much better on arrival.
That's my humble opinion, but I understand we all have different priorities.

I fly F/J >95% of the time, but I would still think twice about it. It's one thing to use a SWU or buy an award ticket, but I would hesitate to use miles+copay or cash on this route. LAX-LHR, sure, but JFK-LHR, maybe, maybe not. It would depend on exactly what I needed to do on arrival and whether I really wanted the dinner/snack on the flight. Sleep would be less of a concern for me. I can get sleep in an MCE seat simply by being mentally and/or pharmacologically prepared to do so, making a lie-flat seat unnecessary, particularly on such a short flight, but YMMV.
Ultimately, it's about what you want/need, how you value that, and whether you're able and willing to pay for it. Outside the world of air travel, $400-500 is enough to provide much better experiences than what I could get in an AA J seat on a six hour overnight flight. OTOH, there have been plenty of times when I've spent more than I would have liked to lock down a premium cabin seat. Sometimes it's a tough call.