Even if your final destination is beyond LHR, if I had the time, I would much rather take the daytime flight and overnight at a hotel in LHR than take the redeye and then connect to my final destination the morning of your arrival. East Coast US to Europe is just not long enough to sleep, even if you are in J. By the time you factor in departure, and service (which interferes with sleeping even if you don't partake) and arrival, there's not enough time left to sleep to arrive anything resembling restful.