I just recently purchased a Garmin NAVI 205W GPS. It really works! And during our CALABARZON trip it was a HUGE Help. It correctly told us where to turn left or right. The GPS will provide the quickest route to your destination, and you do not have to worry if ever you change directions as the Garmin Navi will recalculate the changes and provide another route.
All travellers should have one of these.