One advantage to the rather basic method of using serial comms is that you can easily test each Arduino separately by routing the serial to pins 0/1 and talking directly to the serial monitor on your computer....
Then you switch to NewSoftSerial on the correct pins to get each talking to the other (although the "slave" processor is easiest left on pins 0/1 and hardware Serial)
Once that's working its relatively painless to transition to another method should you desire to.