Does anyone know how the Verizon or AT&T cell phone reception is outside of Glasgow or Edinburgh in the Highlands and Skye? We want to use google maps instead of bringing our GPS unit and wonder if reception is good enough to rely on it for google maps. Thanks.
I can't speak for Verizon or AT&T, but I had a SIM card from a major UK carrier (Carphone Warehouse) and still could not make calls in various parts of the Scottish highlands. I'm no expert about cell phones (to put it mildly), but I understand if cell coverage is absent in a given location, you won't be able to use Google maps.
On other Scotland forums people have recommended investing a couple of pounds in a printed map. They're widely available at gas station convenience stores and from the "i" tourist information offices. I concur, even though our rental car came with built-in GPS. Sometimes the printed map is just a lot easier to follow.
The cellphone reception will be as good as the networks which partner with Verizon or AT&T, and their roaming agreements may allow your phone to use several networks. I've been roaming with my home cell network lately, and find that my phone seems to switch carriers as I move from one area to the next, most likely because of signal strength.
Reception should be seamless in the cities, but I haven't travelled in the outlying areas you mentioned. As I recall, most cell phones are capable of GPS reception even without a cell signal. I've found that there are few areas in Europe where cell coverage isn't available, even on the top of mountains in the Berner Oberland.
I just returned from NW Highlands including Skye and use AT&T. We were able to use google maps with no problem because I downloaded an Offline Google map. You won't have the same degree of detail (icons for restaurants, shops, etc) because you can't zoom in to that level but you will be able to navigate with/without cell coverage. In the built up areas, cell coverage was fine; it was spotty otherwise. just like in US. Also, your rental may have navigation included even if you didn't reserve that.
Reception will be most patchy in the places you need it most, although in the highlands there not many roads to choose from and if a place is big enough to need a decent "citymap" ,Fort William ,Aviemore etc you will have reception
Thank you everyone for your very helpful information.