I'm a cheap ass college student, DePauw '09. I'm taking a trip to Chicago next weekend, Amtrak from Springfield with bike. So, I need a way to navigate Chicago without spending $500+ for a 705 with maps. I'm looking at the Nuvi 250 with a handlebar mount. It will still accurately tell me speed, distance, and time right? It would also be useful in my car, as I don't have GPS and plan to move far away from the midwest after school. I'm curious as to what you all think of this and if anyone has first hand experience using an on bike GPS that is not cycle specific.

Here is the link to the mount:
$16 with free shipping. The Nuvi 250 is on Amazon for $178 with free shipping; I think it's still around $200 in stores, I'm checking this weekend though.

I also looked at the Garmin Quest but it got some bad reviews and isn't a whole lot cheaper than the 250.