Once you start using Uber, you get used to its predictability in most parts of Greater Boston. Request a ride, and by the time you pay your lunch bill or pull on your coat, there’s a car waiting outside. I’ve used Lyft and Sidecar (remember them?), and neither of them ever attained that level of don’t-stress-about-it simplicity.

So I didn’t exactly jump in September when a startup called Fasten, with operations in Massachusetts and Russia, launched its own transportation app. I downloaded it to my phone, but every time I opened it, the closest driver was 8 or 10 minutes away — an eternity in comparison to Uber. (Right now, Uber estimates the pickup time at my home in Brookline to be two minutes, up from one minute when I began writing this piece.)

But on Monday, I had a relatively relaxed schedule, with decent stretches of time in between meetings, a lunch, and interviews. So I took three rides around Brookline and Cambridge with Fasten.

You set up the app just like the other car services: enter a credit-card number or PayPal account for payment, and connect your Facebook account or upload a photo so the driver knows who to look for. When you’re ready to ride, the app shows you nearby cars on a map, just like Uber and Lyft. Fasten offers two vehicle choices: a car that seats four passengers, or one that seats six.

I did wait about 10 minutes for each of my three rides to show up on Monday. (All of the rides took place between 10 a.m. and 3:30 p.m.) But the vehicles were on the high end of what you’d get with Uber’s comparable UberX level of service: a roomy Cadillac DTS and Chrysler 300, and a new-ish Toyota Camry. None of the drivers got lost, relying on their GPS and the destination I’d entered into the Fasten app to find their way. Two were stoic, one was chatty. That last driver, my final Fasten ride of the day, was near Government Center when he came to pick me up in East Cambridge. He called me to let me know he would be there in a few minutes — likely so that I wouldn’t cancel the ride request out of impatience.

One minor annoyance: On Tuesday morning, the day after my three test rides, I got a fusillade of notifications on my mobile phone all at once. “Your driver should be arriving shortly,” “Your driver has arrived,” “We hope you had a nice ride!” etc. That felt amateurish.

The key difference between Fasten and UberX is money — both for passenger and driver. Fasten doesn’t have “surge pricing” that raises rates in times of high demand, though there is a way to “boost” the price you are willing to pay in order to persuade drivers to pick your ride request rather than someone else’s. Fasten says it has no minimum fare (UberX’s is $5.15 in Boston), and no penalty for canceling a request a few minutes after you make it (Uber tags you for $10). Fasten charges $1.10 per mile, UberX $1.24, and you can open the Fasten app while you’re cruising around town to see a running tab. On the driver’s side, the amount Fasten charges for hooking them up with each fare is fixed — about $1 per ride, though the company’s site says there are other options — rather than a percentage of the total. Some may find that more appealing than Uber and Lyft’s 20 to 30 percent cut of each job.

I paid just $5 for each of my first three Fasten rides, since the company seems to be offering a promotion that offers rides of 20 minutes or less for $5. Ordinarily, Fasten would have charged between $8.84 and $10.89 for these three- to four-mile rides. Fasten currently serves only Boston, Cambridge, and neighboring communities like Waltham and Newton.

The takeaway: If you’re more price-sensitive than time-sensitive, Fasten may be worth checking out. (And if the app’s usage takes off, its ability to quickly dispatch drivers will likely improve.) But even with introductory discounts to attract riders, Fasten will need to figure out a way to quickly shift into fifth gear if it hopes to catch up with Uber and Lyft. Despite the occasional gripes about how those services work, they’ve got huge brand awareness and loyal users who don’t think twice before hitting their app icons when they need to go somewhere.