That a PA can be small, lightweight, efficient, and can sound punchier, deeper, clearer, w/ more balanced spread.....just overall 1000X better, and not have to pushing 100+db to make an audience "feel" the music. That monitoring systems are incredible compared to the crap they had in 70. That bigger/louder is NOT better, and that you can do a show in front of 20,000 people playing through a deluxe reverb, not 4 full Marshall stacks.