Asynchronous communication can introduce complexities such as eventual consistency, message ordering, and error handling, as messages or events may be processed out of order or lost. Synchronous communication, on the other hand, is relatively simpler as it provides immediate responses and does not require additional mechanisms for message handling.

Overall, synchronous communication is suitable for cases where immediate responses are critical, and microservices need to be tightly coupled, while asynchronous communication is beneficial for cases where decoupling, scalability, and fault tolerance are important, and delayed responses are acceptable trade-offs.