I currently have a Garmin Edge 200, which I like quite a bit. But I would like a GPS that has mapping capabilities. I don't need the training features. I'm curious about the quality of the maps in the Garmin Touring. It looks like they are based on some sort of open source maps. Does anyone have this unit and can comment on the quality and accuracy of the maps?
The Edge Touring comes with a preloaded "Garmin Cycle Map". This is based on OpenStreetMap, so you can check the OSM website to see how good coverage is for the areas you are interested in. In general, OSM is rather good for roads in most of Western Europe, and much of the USA. Many areas also have lots of cycle paths and trails mapped. It is often more accurate and up to date than other maps. Plus if something is wrong or missing, you can edit the map to fix it.
The Garmin Cycle Map is designed specifically for cycling, so highlights relevant features, eg cycle paths. If using the navigation, it is designed to route you along paths or minor roads where possible. And it contains height data, so it can show elevation profiles or route to avoid hills.
Note you can download other OSM based maps in Garmin format for free, then put these on the Edge instead. These are available in a variety of different styles, which you may prefer. Also they may be more up to date, which is useful if you are adding of editing things on OpenStreetMap.
Or you can buy other maps from Garmin, eg City Navigator, then use these on the Edge. These can be expensive, depending on how large an area you want. And City Navigator only contains roads, not paths etc.
The map-capable Garmin cycling units come with a solid basemap with the ability to add additional maps, and the Touring unit has a micro SD slot to make this even easier.
Granted the maps that come with are good for a point of reference, I wouldn't recommend Garmin's maps for any substantial route finding. If you're trying to find a safe bicycle route around town, use google maps. If you're heading off road or out into the woods, make sure you print out the maps you're using so that you're not stranded when batteries die.
I got the Garmin Oregon 450 and it works great as a cycling GPS. Garmin sells a very good GPS mount for this model as well. It's a little bulkier than most of the cycling specific GPS Units, but for the price you pay, the features are way better then what you would get from one of the cycling models. It also supports loading on maps from OpenStreetMap which will provide quite good maps (may vary by your location). The batteries are standard AAs which will allow you to easily carry extra batteries if you need to.