For code coverage purposes I love the fact that there's only one branch of code to focus on. A lot of my code with streams instantly starts with a return statement and then has a 5-10 lines of stream operation invocations. Very clean stuff.

Streams can tend to be more readable and easier to write for the right problem set. This is because it is super easy to compose basic functions together which are then invoked by the Stream API. It also makes it really easy to parallelize operations.