I've been using Reoon to find potential clients. Because it provides comprehensive contact information, I can build a strong database. The app does get unstable once in a while. When that happens, I quit and relaunch. Then it is ok. It has been a very useful tool for anyone's marketing plan.

Review update: After using it for a couple of weeks, one of the things I am experiencing is messages that it cannot find the requested information. So I quit the app, sign back in, and it may be ok - not always. It does speak of using a Proxy, VPN, etc., which may help. I think this is important to know ahead of time.