At the moment, at least for me, Marshmallow on the Priv is working really well. so I'm not 'chomping at the bit' for Nougat. :) It was a really big improvement over Lollipop. I wouldn't be too concerned with the launch date being 'Sept', i personally don't think thats an accurate timeframe.
Latest in my mind would be 'May' for all unlocked devices and then depends on how quick your carrier is. Nougat is on less than 2% maybe 2.5% of devices at the moment.