Yes Storm is still under active development. Yahoo, Baidu and other big players continue to use Storm.

To be honest Storm's API is richer. Our approach however was to make stream processing available to all developers. It doesn't get simpler than four callbacks:

  void init(CtxPtr context);
  void destroy();
  void processRecord(CtxPtr context, FrameworkRecord &&r);
  void processTimer(CtxPtr context, const string &key, int time);
  Metadata metadata();