In what seems to be a May 2012 newsletter, TomTom pens an article highlighting the limitations of "open source mapping" While the article does not name any by specific maps, nor define what open source maps are, the discussion is clearly about OpenStreetMap.
The article quotes statistics from studies, but does not cite them, but basically argues that the errors in such maps may be ok for pedestrian mapping, where there is more time to consider options, but unnacceptable in car navigation systems.
Richard Fairhurst (@richardf) offers a well thought out rebuttal on his System D blog.
- Did You Know? in TomTom Newsletter via @toffehoff