Wireless sucks. I have two Cateye wireless and they are always off compared to my riding buddy's wired computers. And expensive. And no matter how i position the magnets the speed is always jumping from the correct speed to too low and back again. So I know none of my readings are accurate by the end of a long ride. And the button on one of them gets stuck making it very hard to scroll from screen to screen.
I recently got a Planet Bike Protege 9.0 and it's awesome! The whole screen moves foward to change screens instead of using a small button. Most info is all on one screen so you almost never have to change screens, the distance indicator is dead-on when compared to highway markers and at only $25-$30 it's a steal.