TomTom has them all beat. In fact most of the other purchase the maps from TomTom and have for years. TomTom is the best system hands down - I can tell you lots of reasons why - fresher maps, more options to self correct your maps, community input, user interface, live traffic feeds, user interface. Check out the new one - not sure if it released yet, but the 2405 is awesome, I have a pre-released version.
I'm not just saying this because I work for them, I've had a Garmin and hated it, the battery died all the time, no shut off button etc... If you have any specific question please ask.
No, I don't get them for free either