I've always wondered why turn-by-turn, voice-guided GPS wasn't on the first iPhone, but now I think I know. Having used AT&T's Navigator and many of its competitors, I can only conclude that a full-function consumer GPS is harder to pull off than a 20-year-old tattoo.
Each portable GPS app, service and device has its share of glaring omissions and malfunctions to go along with their inherent utility.
AT&T's new Navigator is a solid product with a couple of promising features, including one that lets you verbally tell the app your destination and one that lists gas stations by price. On the downside, the Navigator (made by TeleNav) is overly ambitious. It depends on a lot of little and big technological pieces to perform the way AT&T says it will. Not all of those pieces reliably do their part, making the Navigator experience a mixed bag.