Oleg has over 5 years of experience developing Android apps and has worked with various architectures from Loaders/Services to MVI. He discusses how architectures have evolved from Service/Loader patterns to MVP and Clean Architecture. MVI is described as having advantages like reliable state management, testability, and forcing better app decomposition, but also potential disadvantages like complexity for new developers or with large states. Common MVI frameworks and concepts like states, flows, and handling side effects are also covered.