On PC You could run the program ITNConverter. The program will show OSM, TomTom Routes, HERE, etc. . I presume the TomTom maps shown in the program are the same then on a mobile device with TomTom
Today on a trip I tried running both the Free OSM on my phone and the paid Tom Tom version on my tablet. While I like many features of the paid TOM TOM version. I have always noticed that there are many mistakes in the naming of towns and areas. For example I live in Bettendorf Iowa. But the Tom Tom version has it listed as Pleasant Valley, Iowa. Also areas of Peoria Illinois are named wrong as are many others. Yet these areas are named correctly in the free OSM version. My version of the Tom Tom maps are due for an update, but why do it if the new version is incorrect also?