Good for hobbyists, enthusiasts, communists, cheapskates, masochists, and people with NO money (who somehow have the need for GPS), and immortals (who love driving extra miles to unforeseen destinations, and spending time on support forums). And the developers who might turn a profit.
But seriously, there has been some really good work done and Garmin could learn a lesson from MapFactor - and hopefully they will.
You may be right in one sense. If I had spent 60 Euros or so to buy Navigon Navigator, I would not have spent so much time on the navigation software. But for me it is just fun to cooperate with a world wide community to improve software and maps. If you are not interested to such contacts but just count the pennies in your purse, just go to Garmin and stay there.
Maybe you have the issues due to the country you live in. I have used the OSM based maps and several apps in the Netherlands, England, Belgium, West and North of France, Germany and Austria. All those countries have active communities and the road maps are excellent. In the Netherlands and Germany motorways are at least as good as Tomtom/Navteq and even more frequently updated than those of TomTom and Navteq, same for trunks and primary roads. New road segments and roundabouts are generally months earlier then on Navteq, Garmin or Tomtom based maps.
Tomtom/Navteq based maps have more info related to turn:lanes and destination:lanes and so on (and way more POIs and house number coverage. Only the Netherlands, Latvia and Denmark have full house number coverage). I want good navigation options and that is what Navigator Free delivers in Western-Europe where I live.
I don't know where you live, but in the USA and in Australia the OSM communities are much smaller and they have lots of work to do.
Also because in some European countries maps and map data is released on some open format license.
I agree with hvdwolf, OSM maps in my country are better than many commercial providers (ahem Garm- cof cof), rivaling even Google Maps in quality and exactness thanks to our community. The only issue is house/building numbers, like in many other places.
f the OSM data is lacking, you cannot expect to not end in farmer fields etc, and this is not MF's fault.