I was a backpack commuter for a while (30 mile roundtrip) and thought is was fine...didn't bother me a bit!

UNTIL, hubby put on a rack and panniers....never ever ever going back to anything on my back nope never not gonna do it not me!!!!!

I have the Ortlieb full suspension rack (had issues with attachment and this one worked the best on my bike...Surly Karate Monkey with fenders and v-brakes on rear. Hubby has a smaller rack but he rides a Long Haul Trucker that has brazons for easier mounting)

Also have the Ortlieb (storm waterproof) panniers...loooooove them!!!