My experience with the app is that it is very susceptible to a variety of noises that throw it off. A big one is the bounce of the cueball when you hit a nice pop. I must say that 1) I rarely get better than 60 or 70% legit readings with the app, and 2) It is vastly better in all ways on an iphone vs an android. When the app is working well, it is fantastic. If you are willing to invest serious money into a radar gun, that can be a very nice setup as well. But, um, the app is $4.99...so end of discussion.
KMRUNOUT
What is the difference between the iphone & Android? I have an Android that I probably used 100 times the check break speed without a single funny reading yet. I also use it at home so there is not much ambient noise.