One of my planned uses for a folder (still looking) is riding to improve my (currently poor) fitness. While a bike computer isn't essential by any means, it might help with my motivation. I've heard about some issues with wireless cyclometers, and wonder about the 20" wheel (i.e. do inexpensive computers allow for programming this wheel size?). The most likely candidate for a folder purchase for me (due to local availablity) is a Dahon centre-frame-folder, such as the Mu P8.