This seems like it wouldn't be entirely practical if you were playing in a loud room, and having to pull out your phone and the device every few songs would be wildly time consuming. I love the innovation, but I'll stick my my TU-3.
Nicely played, but as far as a "lesson" goes, it's super fast, and you jump from calling out frets and strings to just saying "first, middle, pinky" which isn't helpful to anyone who needs to look at their fret board to find the right notes.
I was moving from an apartment to my condo, but there were going to be a few weeks in between, so I needed a place to store just about everything I own for a few weeks. I went in to rent a unit, and Colin helped me find something just the right size. I was able to stack all of my stuff in there, and he didn't try to force me into a bigger unit that would have been more expensive and bigger than what I needed. 10/10. Would rent again.