async:

    async.waterfall([
      fn1, fn2, fn3
    ], function(err, result) {
    });

Q:

    resultP = [ fn1, fn2, fn3 ].reduce(Q.when, void 0);
    resultP
    .then(function(result) {});
    .catch(function(err) {});

If you chain thens in Q, you are not doing it right (imho).