If this Google Trends Chart is any indication, it also appears that users are actively looking for Google Maps and that their mind share in search is growing:
Google has been adding a number of features that should also increase user engagement. They have added expanded Streetview, Community Edits and more. So why then, does Hitwise show that Google Maps has significantly lower weekly average visit duration times than Mapquest and they are not increasing relative to Mapquest?
Google Maps Vs. Mapquest User Engagement by Mike Blumenthal