I tried Virtuo, an app-based vehicle-rental service, instead of a traditional agency. The car was great — but I had some trouble unlocking it.

• I tried Virtuo, an app-based car-rental service, for the first time.
• I rented a Mercedes GLA and enjoyed driving it, but had trouble unlocking it with the Virtuo app.

Anyone who's stood in a long line at a car-rental counter spends some of their wait dreaming about jumping straight into their vehicle and hitting the road.

As someone who rents lots of cars, I appreciate it when an agency helps me get into my vehicle quicker – and that's part of the draw of app-based rental services, which do away with wait lines altogether.

Traditional agencies such as Avis, Hertz, Sixt, and Enterprise are facing competition from app-based services such as Getaround, Zipcar, and Virtuo, in a global vehicle-rental market that will be worth nearly $127 billion by 2028, according to one estimate.

I used Virtuo, which offers high-end cars from Tesla and Mercedes, to rent a vehicle in France. I settled on a Mercedes GLA, which cost $580 for seven days.

No early birds

My flight arrived earlier than expected in Nice, so I contacted Virtuo customer service via the app to see whether I could collect the car 45 minutes early.

I couldn't. I was told I'd receive a text message when the car was ready, and where it would be, but they couldn't get it there sooner. So I waited.

Once I received the text, I rushed to the car. The check-in process was easy: I scanned the car for dents and scratches and ensured everything was up to par, and confirmed the same on the app using the artificially-intelligent damage report system.

Then I unlocked the car using the digital key on my app and jumped in. The feeling was different from when I drove a Ferrari for the first time but it was exciting nonetheless.

Unlocking became an issue

As I drove from France to Italy, the car never failed to impress me, and the going was smooth.

However, I had some trouble with the app itself.

Virtuo's digital key requires a Bluetooth connection between the app and the car. One day, as we were getting ready to go to Cannes, we tried to unlock the car. It didn't work.

At first, I thought it was an issue with my phone, so I restarted it — but after about ten minutes of trying, I gave up and called customer service.

The Virtuo representative who answered seemed to be as lost as I was about the problem. For around 20 minutes, we were locked out of the car and Virtuo couldn't help us.

So we logged into my Virtuo account on my partner's phone and thankfully, managed to unlock the car. I presumed it was a one-off glitch. We drove off.

After stopping in the town of Grasse, I again tried to unlock the car with my phone but it still didn't work. I could lock it but couldn't unlock it.

I called customer service and again, they were unable to figure out what was wrong. So we again used my partner's phone.

While the car was fun to drive, the glitches with unlocking, the inflexibility with my early arrival, and my customer service experience took some of the shine off the journey.

Still, I've been using apps like Virtuo for several years and I'd choose them over traditional agencies. They take away the hassle of having to wait in line, sometimes for hours, even when you booked months ago. Plus there are no agents trying to upsell cars and overcharge you for insurance.

While my experience wasn't perfect, I'd use Virtuo again. And hopefully next time, I can drive one of the Teslas it offers.