We have been doing some tests lately of OpenStreetMap (OSM). Inspired by a customer we realised that it had improved a lot since last time we looked at it. This time we checked out Denmark and Estonia. Conclusion is OSM topology is quite good for routing, but basic information such as oneway restrictions still lack in many places and the road classes (used for defining speed) is not always very strict. We have also noticed many roads are registrered as normal roads, even if they are closed for cars and only open to pedestrians / bicycles.
This means it is a good data source if you are not looking at creating driving directions, but is more interested in approximate drivetime and distance between locations not too close. Such as what you will typically use it for in FleetEngine at a regional / national level.
We have also developed a set of instructions and some applications for processing the OSM files, so they are easy to use in RouteWare products. If you want a copy, let us know.