Info and pictures of the various third party cards seem to be coming in pretty frequently these past few days, so the first ones should be on shelves within a month.
From Sapphire, there's only info on the Pulse version yet, so it's still the waiting game on Nitro or a liquid-cooled Toxic.
I've seen reports that the MSI card will launch the 15th and the PowerColor Red Devil is out the 13th. Sapphire is still just "coming soon" No word on price yet for MSI or Powercolor. Although Overclockers.co.uk lists the Sapphire at £428.99. Which would be $520 US. As good as the 5700xt looks I would get a 2070S for that price. $450 is the mark for me before I move on to the 2070.