No comparison, Tom Tom is the leader in GPS market in Europe. Their advantages: reliable and perpetually updated maps, verbal directions, voice recognition in 30 languages and "help me" feature.
Garmin and TomTom have similar coverage although Garmin seems to have more aftermarket support mapping software products for adventurers and similar road features to Tom Tom.
Tom Tom is a higher choice for people in Europe. So it's better go for the Tom Tom and it's considered better in some areas of Europe more than others.
