Since I upgrade my Nexus 4 and Nexus 7 to Android Kit-Kat (4.4) from Jelly Bean, and use hangouts as my default SMS application, I received Hangouts messages (not SMS) with very long delay. Sending messages works fine.

I need to clear cache and data for Hangouts application on my devices to fix this.

To do this, got to Settings->Apps, then search and select Hangouts in application list, then click on Clear cache, then Clear data. Then Force stop and OK.
Close Setting and start Hangouts…

After that, all works fine for me. Hope this may help…