My cousins husband works for TomTom and apparently google maps use TomTom's old software and their traffic updating is horrible...just saying what I heard.
It won’t automatically reroute you but if you hit the menu button -> route info -> then press the center icon at the bottom of the screen it will look for other routes and display travel times as tabs on the top of the screen.
It doesn’t seem to pick more than one alternative route but every once in a while it will pick a 3rd. The travel times seem to be pretty accurate. I use it everyday