I can only comment on my Virgin Blue (low but not cutthroat budget Australian airline) experience but I have to say that the company has completely embodied the Branson attitude as described in his books. For instance we've been an hour late to a flight (that was fortunately delayed) and not only did they let us on the plane, but they managed to let us check in an unexpected baggage item (they security cleared it of course) - I have no idea what the usual domestic American carrier is like but this rule-bending on favour of the customer and common-sense (humans at all levels to paraphrase Branson) is unheard of on other (particularly traditional) carriers where, for example, you can lose your flight without refund if you are only 25 minutes early to your flight instead of 30 minutes.

Some other comparison points:

- "Web check-in" allowing you to arrive anytime up to the boarding of the plane (if flying with purely carry-on luggage) instead of having to arrive an arbitrary time before departure because of inefficient passenger processing.

- Friendly, bouncy and joking flight staff versus off-putting and critical drones who seem put out at the slightest request.

- Modern aircraft with simple amenities like screens for every seat versus tired old planes from the days where lack of competition and government monopolies dominated the industry.

- Reasonable fares without sacrificing quality versus either dated but comparable quality at a higher price or true "budget" where you sacrifice both quality and patience for a price that is often pretty close after hidden fees (e.g. A fee for booking, a fee for paying and a fee for paying via credit when this is the only accepted option).