in an isolated environment, wireless would be the same as wired for internet based tasks, as the connection speed of your local WiFi is typically faster that what your internet service provides.
In real life, wireless suffers from interference (garage door opener, microwave, etc) as well as contention with other devices (your wireless devices, your neighbors wireless devices, your neighbors wireless networks, etc...) Not to mention that wireless has additional overhead in order to get the same bits to your machine compared to a wired connection.
I keep anything high bandwidth or timing sensitive (like VOIP) wired, and reserve wireless for smartphones and tablets...