The debate that raises more opinions than the "secondary or no secondary" debate. There are more reasons to cool wort to fermenting temperature and then pitch than there are to pitch in the 70s and then cool, but chilling wort to 50 degrees isn't the easiest road in the world to take. If you can chill to fermentation temperature (no more than 55 degrees) and then pitch, then do that. If you can't, then don't. But cool the wort as much as you can and get it down to fermentation temperature as fast as you can. Off flavors for lagers, including diacetyl, will be produced during initial fermentation if the wort temperature is in the high 60s / low 70s.