On my recent trip from Dallas to Toronto, I had planned to use my Microsoft Streets and Trips along with USB based GPS (thingy I purchased online). However, when I got to Dallas I was surprised with a Tom Tom GPS from my family for my trip back home. So I had the good fortune to try them both on my way back home.
What I liked about Streets and Trips was that it was able to give me a big pictures whereas Tom Tom didn't. Maybe it could but not as good. Having the large state/city map would also help.
What I like about Tom Tom was that it was small and easy to operate. Streets Trips required too much stuff (laptop, inverter, etc).
Tom Tom was very handy while in downtown Dallas looking for something specific and missed the exit as I thought I new where I was headed. Immediately started my GPS and was able to re-route in the right directions.
In addition, Tom Tom works great in Canada without any modification and it shows all points of interest (even more points of interest then Streets & Trips) as it does in the US.
So, I would say 'YES' to TOM TOM in the city, but when you are on interested and ready to travel long distance, you need that big picture and need either paper map or something like the Streets & Trips.