WiFi Picker(Scan Wifi) helps to find good AP(access point)s and to connect them graphically.
1. Signal strengh
2. Channel number
3. Security type
4. Link speed
5. Hardware vendor
6. IP number, and etc.
You can see which one is good and bad intuitively, and it is very easy to use.
Also, this application provides "Query nearby network devices" feature.
It scans all connected devices to your AP.

WiFi Picker also supports notification feature with various network information.
(Link speed, IP etc)