They would be what you paid for. Cheap ones might be dirty, more expensive ones fancier. Unlike taxis, where your choices are "take the first one you see" or

They would be what you paid for. Cheap ones might be dirty, more expensive ones fancier. Unlike taxis, where your choices are "take the first one you see" or "wait a long time for a called one to come" the rule would be "the closest one to you that meets the standards of the company you asked to send one" comes. Or if you are in a real hurry and did not plan ahead even a few minutes, you take the first one that might be dirty.