There is no such thing as wireless HDMI. Note the name of the Gefen product is Wireless for HDMI, not Wireless HDMI. There are a number of things to take into account when making your decision. The signal is compressed. Supposedly users cannot tell the difference. It is a HDMI 1.2a device (compatible with 1.3). Maximum claimed resolution is 1080p30, sufficient for BD (1080p24). Bandwidth is insufficient for Deep Color (make sure you turn it off on your gear). Maximum distance is 30' with nothing but air in between the transmitter and receiver. Put anything in between, and that distance is less. Even people walking between the antennas will affect range. High resolution audio is not supported. Bandwidth is insufficient for 3D. Any RF device is subject to possible interference. And it ain't cheap.
Considering all of that, IIWY I would go hardwired.