I used the Cab3 app yesterday for the first time and I really liked it. It was my first time EVER to control a train using anything other than conventional control, and it was a blast!
I would encourage people to read the directions on the website or watch a video before using it, as it was not intuitively obvious how some of the features work or how to access the other screens besides the home screen.
A few very minor negatives:
1. I found that swiping to get to screens other than the home screen was a little balky. I assume it will get easier with practice.
2. The app does not allow multi-unit consists. That's about the only Legacy feature I care about that is not included in the Bluetooth app. I'll probably break down eventually and buy a Base 3 in order to do that, but I have higher priorities for my model railroad budget right now.
I would encourage anybody to give the app a try - hey, it's free! Thank you, Lionel!