The component is a bit more expensive on a road bike than a mountain bike and it will normally weigh less. I'd recommend going with a used bike, the Newest 4.0 has the lowest level Shimano components offered and down tube shifters, which you may or may not want. For this price, you could find a pretty good quality used road bike. If you really want something new, look at the Raleigh sport; I road last year's model and it seemed pretty good for the price at the LBS ($430 on sale), but it looks like they are discontinuing it this year.