Great for wireless debug as well. We had an issue in the early days of WPA and Wireshark was one of the first open apps to support sniffing and decrypting WPA traffic. We also used Omnipeek, which had a better GUI and better promiscuous and monitor support but Wireshark caught up and now it's my go-to tool.

Filter syntax is a headache, though, if I remember correctly it's totally different for capture and display. I have to go to the manual every time I use wireshark.