I have a Tom Tom One and I am not at all happy with it.
Even though I do updates, it is missing tons of roads and businesses.
Yesterday, I was searching for this obscure store in Charlotte, NC called WalMart. According to my TomTom, there aren't any. (There are, I looked on line).
The other day, it had me go 2.5 miles, through a series of back streets, to get to a store rather than simply going past it and doing a U turn.
It seems that the TomTom does not have the ability to search beyond the destination route for a better, quicker alternative.