Flying domestic US flights are very different from flying down under. So please set your expectation low. Please remember most of the passengers are elite passengers upgraded from economy for free! So the service reflects it.
Between DL and US, I will pick Delta because Delta is less LCC than US.
In terms of food and beverages, Delta has this snack basket service on most flights over two hours, which is nice. Bananas, apples, Sun Chips, M&M, peanuts and pretzels. Meals also appear on flights above three hours and during meal hours - 5 to 10am breakfast, 10am to 3pm Lunch, 3pm to 7pm Dinner, and the rest of the time, there will only be the snack basket service. However as a frequent AA and DL flyer, and occasional UA flyer, I definitely appreciate Delta more than other airlines. It is one of the better airlines.
Virgin America is an unusual airline and its first class service is definitely top notch. it is the only US domestic carrier that offers a proper business class lounge type seat with 55 inches of legroom on all its narrowbody fleets. But VX also does not offer any "free" upgrades and has no elite passengers. They have a very good "buy up to first" program - you can pay an upgrade fee if there are first class seats 6 hours prior to your flight's departure time.
About luggage fee, Delta is very generous by allowing three pieces of luggage per passenger if you are confirmed in first and business. And I really don't think there are other airlines in the world that allow you more than three pieces of check-in bags and each piece can weigh up to 70 pounds.
Anyway, domestic US F is like flying premium economy, so please set your expectation reasonably. Since most passengers are "free" upgrades, you can't expect too much!
Carfield