Personally, I prefer to head west earlier rather than later. It doesn't matter how you do it, you'll still end up waking up a few hours early the first few days. At least if you out earlier you get extra holiday time at your destination. Time to arrive, take a shower and head out for the afternoon/evening.

Coming home, wthout doubt, the later flight is better. I've arrived home at 6am in the past and having to stay up all day is a nightmare. Also if you leave late, you are more prone to sleeping on the flight.

So, get the early flight out, the late flight back.

Of course when I put my FT head on I start considering bump opportunities, 747 vs. 777 (usually fly UAL to west coast US), upgrade strategy, good seat availability yada yada so all the practical considerations go out of the window!!!