Actually, how hard it is to get working seems to depend on a lot of things including the size of the frame. The distance between the pick up and the computer head are critical and sometimes if the brake caliper for example is in the way, it will disrupt the signal. You have to install a magnet on one of your spokes, a pick up usually on the front fork, and a mount on your handlebar. The computer head clips in and out of the handlebar mount.

When I install a wireless computer, I mount the wheel magnet and pick up first. Then I clip the head into the handlebar mount, hold it close to the pick up on the fork, and spin the wheel. If I get a MPH reading, I know that it's working. Then I hold the head unit close to where I plan to install it on the handlebar and see if it still works. If it doesn't, I try to figure out where I have to mount the head or how to move the pick up to get a clear signal. If you have average or better mechanical ability, it's a piece of cake.

Wireless Flight Decks really aren't wireless. You have to connect a wire to each of the shifters. If you are getting a wireless computer to make the installation easier then a Flight Deck might not be for you. Connecting the shifter wires and programming the head are the two most involved parts of the installation so getting the wireless Flight Deck won't save you much installation grief.