My preference is coach to Europe and Business to the US. I usually have two (or more) bottles of wine in coach and fall a sleep for the balance of a 7 hour flight, especially since its normal bedtime. Coming home, with the daylight, I can't sleep in a coach seat and I find that I can in a Business seat. I would say the only reason to do it the other way is that the meal on a Dinner flight is usually better than on a lunch flihgt.