My first reaction was that 70 million is an insane amount of money for a keeper, but that's only because keepers tend to be undervalued relative to outfield players. If we were talking about 70 million for a young, top class striker then nobody would bat an eyelid, which is weird because a good goalkeeper is just as (if not more) important to the team as a good scorer.
So, assuming he's as good as everybody is saying, I'm all for it. Considering his age and the way transfer fees are going, getting him now might even be considered a good investment.