I posted earlier earlier this month regarding the issues I am having with the on board WiFi. Well those issues are still plaguing me. Repeated reboots accomplish nothing with the same negative results coming from clicking on the network icon on the task bar, selecting the WiFi network, entering the passphrase and hitting OK. I am completely stumped.
The ping times during the occasions when the on board WiFi was up were ridiculous. Anywhere from less than .99ms to 21000.0+ms. I disabled the on board WiFi by adding "dtoverlay=pi3-disable-wifi " to the boot/config.txt and plugged in a reliable WiFi dongle previously used on a Rpi2+. At first it worked great but soon developed similar (but not as worse) symptoms as the on board WiFi.
I'm currently running the Rpi3 with the on board WiFi disabled, a WiFi dongle and the Ethernet port. The Ethernet port works 100% of the time, the WiFi dongle is good about 75% of the time.