Cap rate pro app

[Luis Saez]

I found what I think is a good app to calculate cap rates. It's called cap rate pro. Have any of you guys used it and if so is it good. Mind you I'm still a noob. I've been going over lots of properties trying to figure the numbers on paper. And this seem to make it easier. I've also stumbled upon a book that I'll be getting by frank gallinelli about cash flow and the formulas used to determine a good investment vs a bad one. Any one read this book before and if so is it worth while?