I used my first 3 unlimited hours. Although there were a few glitches, like not seeing the time remaining in the app until the end, it worked pretty well. Now though, the app systematically crashes when I open it. I can't even see the option.
It had been 2 days since my last use. Uninstalling and reinstalling had no effect, and I made no changes to my plan. Now this morning, I can see the feature again. I guess they fixed the app maybe. I'll see if it works on the road.