Adding to weavejester comment, back-pressure is to be handled with core.async channels [1]. I guess in Rich's terms, RX/FRP "complects" the communication of messages with flow of control [2]. Although this last statement may not be true anymore given that RX now has many functions to control the scheduler (eg. observeOn/buffer/delay, etc).

[1] http://clojure.com/blog/2013/06/28/clojure-core-async-channe... [2] http://stackoverflow.com/questions/20632512/comparing-core-a...