I bought this map for my tom tom one which is getting on a bit now a few months ago for £39.95 and my view is that it is worth every penny! We go to the USA at least once a year and inevitably end up stressed and screaming on the highways because we are lost!!
However the roads this year were made much more bearable with this map and my tom tom in tow! It would have cost us around £30 to hire sat nav in USA with a hire car company and we have this map or good now so I saw it as a cost effective exercise.
One of the best features of the map was the fact that it had a system switched on whereby it told us when we were exceeding the speed limit- and lets be honest - I wouldnt want to get caught in USA speeding. Bad point were sometimes it took us a longer way than a route we knew - but my theory is if you know better you can always ignore it. The quirky USA accents were funny too!
As far as actually buying the map went, I had to buy a memory card, buy the map, load a tom tom programme on my PC, plug my TOM TOM into the PC and load the map to the card. Even though it was meant to be staright forward I did mess up, but TOMTOM support helped me sort it! So if you are a technophobe- its worth getting someone who has a clue about PCs to help you load it ( Worth noting it took me around an hour and half to load)