I also bought the Pro version of the app.
I have had zero problems with it. I leave it plugged in all the time.
The only thing to watch out for is don't leave the app running when you are in Bluetooth range of your Nissan Leaf.
It will cause a relay to click over and over, adding wear and tear, and using your 12 volt battery. You will hear it when near the car: it's a very audible erratic clicking sound.
If you're not familiar with the app, click here to see it on Google Play. I used the free version for a while, but I think the Pro version is worth the $15. There's also a 'midrange' version here.
The free version is here.