This app requires technical knowledge about wifi configuration. Most of the negative reviews are from people who have not configured their network correctly for roaming operation. There is a forum on heleron.com which provides help.
You can see a full description of what this app does in the description of the "Wifi Roaming Fix" app. This is a new improved app called "Wifi Roaming Fix", which we recommend you try first as it is more efficient than this one. (In a network of multiple APs set to the same SSID, this app selects the strongest AP).
This app does not switch between networks that have a different SSID, because this is not allowed for in the wifi roaming specifications.