I've had a sigma 1609 and a cateye triple wireless.

Sigma is cheap and wired. $35 on amazon I believe so you can have the same on each bike. It works great if all you want to really see at once is speed and cadence then look at distance later. After about 4000 miles on rough road the handlebar mount often wouldn't seat the computer well enough to read cadence. I was using a wrist heart rate monitor with it which was difficult to read and it going out I upgraded.

The cateye triple wireless was $130 on amazon. It includes wireless speed/cadence and heart rate monitor strap. It is great except the text is quite small for cadence. Let's me view speed, heart rate, cadence, and distance at once. Doesn't drop signal like cheaper wireless computers I've had and is built really well. Heart rate strap seats better than my stand alone one which also lost connection where the cateye is solid. Only negative is the menus are a little difficult to navigate coming from the sigma but after a few times of use it is fine.