Curb does have a nicer splash screen than the three ridesharing apps, a sort of animated roadway that spells out the company name. You register a credit card (though, unlike the others, you have the option to pay cash for a ride if you want — it's a regular taxi, after all). As with Uber, you can enter your credit card number by taking a picture of your card.
When you launch the app, it comes up with two options: I'm Ready To Go and Pick Me Up Later — it's the only one of the apps that lets you schedule a ride in the future, handy if you're going to the airport at 5 a.m. Unfortunately, that option isn't yet available in San Francisco, so I wasn't able to try it out.
Clicking I'm Ready To Go brings up the familiar map with your location marked on it and the app's best guess at your address. One thing I can say for Curb, it was the most accurate at determining the proper address. There's a Pick Me Up Here button and an ETA for when your cab will arrive. Pressing Pick Me Up Here brings up a screen where you can set your destination and get a fare estimate. (Curb is noticeably slower than the other apps at coming up with that estimate, however.) At that point, you click Book Ride. So far, so good.
The problem comes when the app starts trying to find you a driver. You get a warning that you that you may be assessed a fee if you cancel the ride after a driver accepts it. That wasn't an issue, though, because I never got a driver to accept the ride. The screen displayed "assigning ride — thank you for your patience" for five minutes, and then finally announced no rides were available. That happened all three times I tried to use it, including one occasion that, had a driver picked me up, would have gotten the cab downtown just in time for rush hour. (I thought that'd make me an enticing fare.)
I can't help wondering if the "availability" of rides is really a euphemism for the willingness of a driver to accept the assignment. If you try to use Curb from a busy neighborhood, there may be taxis close by, but they can probably get hailed easily enough on the street and don't need to respond to your call. And if you're in a quiet neighborhood, they're probably not nearby and don't want to drive for 10 or 15 minutes to pick up a fare. Whatever the reason, the Curb app is a fine front end to a not-very-functional service.
Sign up for CIO Asia eNewsletters.