I have a computer with cadence on my road bike, and I really like having it. As a newbie rider, it has given me a sense of what gear I should be in to spin in a good "zone." As I gain experience, I find myself referring to it less and less on the flats, but I still use it for climbing. I use a Sigma "double wireless" computer, meaning that both the speed and cadence features are wireless.
IMO, it's a good computer and reasonably priced. Here's a link: http://www.sigmasport.com/en/produkt...punkt=features
I also have a Cateye Astrale 8 on my hybrid that has wired cadence. I prefer the Sigma as it gives me less trouble. The sensor on the Cateye gets out of place easily.
Live with intention. Walk to the edge. Listen hard. Practice wellness. Play with abandon. Laugh. Choose with no regret. Continue to learn. Appreciate your friends. Do what you love. Live as if this is all there is.
--Mary Anne Radmacher