The last Sleeping Beauty was not so bad, it's not yet part of Platinum Edition then.
But I think owners of that can skip this, unless they want to own each and every one of the PE.
Having owned that one, I think the one to get is the Bluray version, since eventually all Platinum versions will get that treatment... Just like Snow White PE, the first to (new) format, will be the hardest to find (eventually)...