For a couple of weeks was me, my girlfriend and a friend visiting Unites States, we visiting New York and drove around by car at the west side of the country. Under the two weeks we was there we travelled over 400 miles by car.
To navigate we used my Nokia Lumia 920 and the Here Drive+ apps that comes with all Nokia Windows Phones. I have downloaded all maps before we left Sweden.
I was a little bit unsure how it will worked before, but people on a Swedish group for Windows Phone users told me that it will work fine. I have used it in Sweden with good result earlier but I asked for to be sure. All we talked about before told us it was a good idea to bring a GPS.
The people on the Windows Phone group had right it worked very well, I am impressed that a free app could work so good (it coast a few dollar if you do not have a Nokia, but it definitely worth it). We used it not just when we went by car, but also when we walking in big cities like New York.
To have something to attach the phone to I brought my Nokia CR-200 holder with build in wireless charging that I bought earlier this summer.
To use my Windows Phone instead of renting a GPS, we saved pretty much money that we could use for other things.
If you is to buy a new phone, just Here Drive+ is a reason enough to buy a Windows Phone.