More efficient:

• Task creation does not use dynamic allocation unless explicitly requested, even for sophisticated task trees containing continuations and logical dependencies between tasks.
• Type information is exploited as much as possible to avoid doing redundant work during runtime.
  • No redundant internal synchronization.
  • When dynamic allocation is requested, only one block of memory is allocated, even for complex task trees.
• Exceptions are only caught and marshaled when it is possible for the user-provided function to throw.

Cleaner design:

• Concise, unified syntax for tasks and task groups.
• The library relies on generic lambdas: as a programmer, you should not need to remember and spell out types that the compiler can infer on its own.
• expected<T> is used marshal exceptions.