I have been using TomTom for more than 3 month. (I also tried Mapopolis and Destinator 2) My personal experience as follow:
Pro:
1. It's has the best user interface. (best looking and easiest to use)
2. fast re-route
Con:
1. Their routing algorithm has a problem for long trip sometimes. It gives route that is not logical at all for long trip (eg. From San Jose International Airport to LA will make you drive 80 miles more!!!)
2. Navigation view doesn't show any street name which can cause problem in small city.
3. the 語音導航 only tell U "when" to turn by "distance", not "where" to turn by "street name", "freeway exit" or "freeway direction (north, east, south, west)", which is quite confusing in knowing when to turn when it says "Turn right in 200 yards", where all the exit are on yr right and they are very close.
P.S. But it's still the one I use most since I found others are hard to use.
My SE X1 rom-> http://forum.xda-developers.com/forumdisplay.php?f=471