Tethering via LAN or Cat 5 cable use allows for a really positive lock to the camera and cheap and common cords in endless lengths. I just received my new 1D X (2/2013) and I have tethered every opportunity previously with the 1Ds MkIII etc.
The problem always was the weak connection to the camera and even a small tug can lead to a disconnect and at times requires a whole reboot of the computer to get the software/camera to talk again. I actually like EOSUtility for all it's functions and that it's free. It's much more than a shutter release.
The speed of transfer via Cat 5 from the 1D X seems to be comparable with a USB cable to the Mac, But the connection of camera to computer via the Wizard is taking 2 minutes 20 seconds - an eternity during a break to reconnect for any reason. USB can take 10-20 seconds and that feels bad but 2 minutes?
I'll most likely continue using USB unless I can speed up the connection initialization.
In time I'll figure out manual settings which might speed things but since little exists on the subject of how to and settings up outside of the Wizard I'll post here anyway. I know it's an old topic.