That's who I use, however I believe that if you recommend someone who applies, you and possibly them get a discount/extra credit.
Quite fun last year driving through the toll at 30kph. And it saves all the hassle of undoing 3 point harness (in my case) and running round the car to collect the ticket, finding somewhere to keep it till the next toll and then trying to find it, along with the change. Does cost a bit to set up and run, but worth it for me.