Personally if thinking of jet lag, the daytime flight is the best, by getting up very early you're already getting adjusted to the time change and after arrival and dinner can get a good night's sleep. The 184 is the worst from my point of view, leave too early for sleep and arrive around midnight US time but wiped and unable to really do anything.
The other alternative, which you don't mention, is the very last flight, around 11pm That would be my second choice. You can have dinner at the airport and, depending on your age etc take a sleeping pill for the flight. You'll wake up early hours US time but able to enjoy your afternoon and evening in London and in most cases the hotel will already have your room when you arrive. Also you don't lose a PTO day. I've tried all these over the last 40+ years and my choice is first or last flight.