Should i buy an Iphone 3g or a TomTom Gps?

My birthday is coming up *19 yay!* and my options are to get an iphone or a TomTom system. now normally i would just pick the iphone, but i have a question regarding the Gps on the iphone. does it have spoken directions? and which do you think is better? i drive around a lot and tend to get lost. lol. thanks so much for your help!

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