Basically it's pretty much the same idea as Autoroute, and has support for GPS (e.g. the little Bluetooth gizmo I got a couple of months ago). I don't think it's quite as user-friendly as Autoroute, and it's a bit elderly - but apparently 2004 was the last release, since then they've gone over to selling satnav systems only, and there don't seem to be any other dedicated OS-X route planning programs now that Macs can run Windows programs. And road layouts don't change incredibly fast anyway.
Anyway, it works, and I can now locate my house on the map with pinpoint precision. More to the point, it might be fun to use it on train journeys etc., it apparently does a moving map view - for obvious reasons I'm not going to try on a motorbike! - and for environmental studies with datalogging etc.