I have Tomtom Rider, Garmin 2720 and a Ipaq with GPS so can compare.
Tomtom OK for basic A to B - until it goes wrong and you join the I hate Tomtom Service Club.
Go for Garmin. Better GPS, good PC software and vastly better back up service.
The Ipaq came with Tomtom Navigator but I have since installed Garmin software, much better.