My opinion that if you have needs to check launch ...

# coroutines

[gildor]

My opinion that if you have needs to check launch result you should use async instead. Otherwise one can misunderstand how Job works and believe that you can omit error handling for launch.
Deferred behaves identically for different environments/UncaughtExceptionHandlers, provide strict semantics and client knows what to expect (get result or catch an exception)