Phone GPS is nice, but not always reliable, that is to say if you have no data service you are hosed. I have been in several states, Montana and N. Carolina for instance, where I have had either no cell service or data service. Here in Europe in the mountains you are lackey to get any service at all, and if you cross over into another country the roaming charge for data is astronomical. I one left my data service on while roaming and it ate through 25 euro, 35 dollars, in 40 minutes.
In America, a technology rich nation, we are so spoiled. All my Italian friends love to see and hear the GPS at work, that is because none of them even own one, let alone have a vehicle integrated one. I for one love not having to bust out the Rand McNally map and plan my trip and I don't miss the endless reams of MapQuest printed pages trying to read while driving because my significant other is not so good navigating.
That said, not trying to rant or flame, just my thoughts on the NAV, but yah it could be better.