What is special about IOTA?

Could you elaborate on the unique features and advantages of IOTA in the cryptocurrency and distributed ledger technology landscape? What sets it apart from other blockchain solutions? How does its Tangle architecture enhance scalability and transaction throughput? Also, how does IOTA aim to facilitate the Internet of Things (IoT) and enable microtransactions for machine-to-machine economies? Lastly, what challenges does IOTA face in terms of adoption and scalability, and how is the team addressing these issues?