If I am in a hurry, I use a pump like the one shown below. I like it because it is not super fast like my big pool-draining pump so I can control where the water goes. In fact I use the water to wash a truck or water the shrubs. Keep in mind that if you are using Dichlor, and if you haven't added it in the past 24 hours, the water in your tub is most likely better than your tap water - use it in the yard.
If I am in a big hurry, I pull out the big gun, but I have to run a pool vac hose out to the street or I'll cause flooding in the yard.
If you don't want to buy a pump, just run more hoses. The built in drain is nice, but not real fast. If speed is important to you but you still don't want to buy a pump, just put the hoses over the side of the tub and start a siphon. When I change water at home I do this: I have four regular garden hoses, and I put them over the side. 500 gallons in about 20 minutes give or take.