Physical location of MP Exchange Service? Equinix Sydney

What is the current service level agreement provided for this service? 99.999% uptime

Is there any encryption for the MP Exchange Service? If so, who holds the key?

Encryption is available, backed by a globally recognized Certificate Authority. They use standards-based technologies—such as Public Key Infrastructure (PKI), S/MIME, and X.509 certificates—to establish confidentiality, message integrity and user authentication. They also include transport-layer encryption via SSL from client to server. The key is held on the  Exchange Server.