I also used to use it off road, as I have copies of a whole heap of topo maps all over AU as well. As others have mentioned, not great for road navigation, as even though the maps are digital, they are simply flat images of paper maps where the maps are calibrated to co-incide with your current location from GPS NMEA data; pretty much a moving map showing your location, speed etc. It doesn't actually recognise the fact that you might be on a road, and if you have a destination set, it can only tell you how far away it is in a straight line. Best to actually get a demo from someone who has used it, if that doesn't make sense. I've pretty much stopped using it now and I use the Garmin topo maps that are actually digital maps, not an image of a map.
It really does come down to what you want to use it on, and how you want to use it, but for my mind, on a bike you'd need to use it on a small screen device with copies of all maps loaded, and the main benefit comes if you have topo maps to overlay. Great software for specific needs, but I suspect a bit limited for road use.