All I can say for sure is this, just wait and see, don't jump head first into buying something that you don't know or understand anything about.

If I knew about the hashrate of these cards and if it was really good(When I say that, I'm talking 4x the performance of the 500Series, and getting nearly 2-4times Per/watt than 500 series) then I know the difficulty of mining for AMD cards is going to skyrocket and we'll have the good ol days of Trying to mine bitcoin again with GPU's ahh good times...(Not really)

But seriously just keep an eye out, I hear its supposed to be great, just not so much when the demand pics up, and it will... if its as great as rumors hint it'll be... the 500 series won't be as efficient to mine with anymore.(Don't take my word for it as it's just rumors)