Not as useful as I had hoped.

Only one route is suggested, which seems to heavily favor bike paths rather than more efficient routes, with no way to set preferences or choose alternate routes. You cannot begin a route from anywhere but your own location. The solid black line of your route often blocks out street names, and the distance of your route is not displayed until you open the turn by turn directions. Good luck trying to memorize all the often unnecessary turns, many of which seem to be added to avoid busy streets at all costs. Sometimes the results can be comically convoluted.

Greg T in Berkeley about Get There By Bike - Interactive Bike Maps for the Urban Commuter