Payday 2 now has a specific, official release date. Pick up the cooperative shooter on August 13 via Steam or wait a bit for retail stores to get the game in stock between August 13 and 16. Yes, there's no official single date for the retail release, just window. Give Overkill a break, this is their first move into retail! It'll be worth the initial confusion.
I have had nothing but outstanding experiences with Payday 2. I'm gnashing my teeth just thinking about how much I'd love to be playing it right now. While it's a little worrying that the release date wasn't hammered down until the week prior, it's likely more to do with Overkill wrestling with Payday 2 now being a retail release on top of digital.
Pick up Payday 2 for PC via Steam August 13 for around $40 or $60 fo the collector's edition, or check out your local retailer for the Xbox 360 and PlayStation 3 versions between the 13 and 16. If you thought Payday was good, then you are absolutely unprepared for how much the series has evolved.