[vsl]

They seem to be more robust, but boost::future::then() has weird design that makes it all but useless for real-life use. They return the same kind of future that std::async() does, i.e. its destructor blocks until the future is ready. In other words, you can't write "fire and forget" code:

    void run_and_report()
    {
       something_long_running()
       .then([=]{ report_results() });
    } // blocks here until the then() block executes