Shower thought. Monero is technically the most private cryptocurrency, and the best to do it, BUT because of its smaller anonymity-set, it perhaps could be debatable if it indeed it's more private than Bitcoin, no?
Every time you make a Monero transaction, your client picks 15 random inputs from the blockchain as decoys, hiding the true sender, and then it derives a one-time public key that's used to obfuscate the receiver, while simultaneously hiding the amounts transacted every time. And if those weren't enough, all these privacy gains are enforced compulsorily, by the protocol.
It's not debatable.