I use the app for daily, fixed fee parking at my local commuter train station. It has been a huge improvement over the prior arrangement - a step into the modern era and the elimination of a near-daily source of aggravation.
Previously, it was necessary to pay the daily fee at a machine. While this option still exists, I avoid it like the plague. The machines have a years-long history of being temperamental:
Refusing to accept cash, rejecting perfectly good credit cards, crashing etc. This performance often had to be undertaken with a train pulling into the station and 3 other commuters in front of you in the line for the parking machine.
Now that this app has been introduced at this location, its goodbye to all that! I just walk casually past the lines of frustrated parkers angrily jamming credit cards in and out of the old machine, paying for my own parking with a few taps on the way past.
On one occasion, I had to make a trip out of town on short notice during the workday, necessitating an overnight stay. Previously, there would have been no way to avoid a ticket for the following days unpaid parking. However, I was able to pay for day 2 using the app in just a few taps from 300 miles away.
I have not used the app in an hourly parking situation so cannot comment directly on that here. However, I would note that the app keeps me very well updated on the expiration of my paid parking, through both emails and text messages.
Its been great.