Lisa.
TomTom is a fine product.
Before you sign up to a UK subscription TMC service you might care to check out some of the numerous Satnav forums like this forum.
The area you live and travel from may be in one of the many black spots or you may live in an area where there is little coverage and travel in such areas.
I would also advise that you ask some forum users with your Tom Tom how they get on with it and ask questions about the vehicle you will use it in. For instance some Fords and Renault's have reception issues re their windows.
James