1. Works well, it's good enough for any amateur or semi-pro to get needed results.This app is not ready yet, it doesn't have option to adjust the resistor.
2. It designs the circuit for you with proper resistor values.
3. This is a great app if you are a modeler and want to light your models with LED's.
4. I suppose there are other uses but that is why I use it.
5. Very handy.Really good app.