My brief experience with my Garmin Nuvi isn't exactly showing it to be much farther along than the Tom Tom. Its ability to navigate seemingly simple routes through local neighborhoods was surprisingly poor. It's clear the software is desperate to "snap" you onto the nearest road, which leads to unusual behavior when you leave the road to go in a driveway or something. I was in an apartment complex when I saved the location, and it's now convinced that the location in question is actually on the nearby freeway entrance ramp.

Part of the issue, I suppose, is that I've become spoiled by the iPhone. It's so much easier to type on the iPhone than the Garmin. Zooming and scrolling with gestures on the iPhone is so natural compared to monkeying with the Garmin's soft buttons. Apple really needs to engineer its own turn-by-turn nav software rather than just letting Tom Tom do the work.