MapFactor Forum

TomTom maps have more consistent routing attributes resulting in more reliable routing, more house numbers and POIs, motorway signs, lane advisor...
TT maps are usually updated quaterly and are approx half price - you can update at any time, no need to do it every quarter
imports are visible in both versions
import is the same, no difference

OSM Maps are much more detailed than tomtom Maps (+ one third). A survey from Heidelberg University found in 2012 that the lack of navigation data in OSM prevalent at the time of the study will be closed by the end of 2012 (now it's 2014!). The survey was for Germany. What is at least still true, are missing housenumbers in OSM Data.

I also have the horrible TomTom app on my device (bought one of their 50% off offers); I suppose that routing would be more or less the same with Navigator using TomTom maps.

90% of the time Navigator Free's route is as good as or better than TomTom's. In those cases where OSM is worse, nearly always the problem is very minor - typically I'm rolling along a major road, and suddenly Navigator wants me to turn at right angles into a residential area, go parallel to the major road for a few hundred metres and then turn left again and continue on the major road.

I have actually used TomTom in preference of Navigator only once in the year or so since I bought it: in that case the best route was a country lane, restricted to 50 km/h, winding its way through a maze of villages; TomTom had me follow that route, whereas Navigator wanted to lead me through every single village, going right/left/right/left... like a hare running away from a pack of dogs.

A much more annoying problem than the occasional strangeness of the proposed routes is the fact that the information that you'll have to leave your current road and join another one is rather inconsistent (though in Germany at least it is slowly improving).
Usually you are told "Turn right in 200 m", but every now and then it's "Turn right" when you are already at the intersection.
I use Navigator nearly every day, and in the past year or so there were about half a dozen occasions when I had to go past the turn-off point and turn back at the next occasion.