Looking to Upgrade from R9 280 ... Should I buy a gtx 1070 or 1080 now, or wait for the 1180 to change prices?

[Swiftest]

The title says it all. I've got an AMD R9 280. I've been considering upgrading and prices are starting to drop. Should I go ahead and upgrade to a 1070 or 1080 ($470) or should I wait for the supposed announcement of the 1180 on 08/20 and hope for a price drop then?

 

[das_stig]

1070/1080 still a good upgrade, expect the prices for a 1180 to be horrible, but waiting may see the 1070/1080 prices drop a bit once the market has enough stock floating around.