AT £420 I think this is overpriced.
It might look like a good deal when you think of 7970 prices, but when you remember that its $499 USD + VAT = around £377 we're getting ripped off in a country where you earn less and get taxed more than the US
It's always been this way. If the GTX680 is better than a 7970 and comes in at £420 then its a no brainer, get the GTX680