Well, I'll try to be more specific.
First, nRoute works, but the user interface is horrid. Keyboard shortcuts are e.g. Ctrl+character. Why? It's not like we are entering text and need to use modifier keys. Why press Ctrl+N instead of only N? When driving this is a major distraction.
And the rendering is both slow and ugly. I get faster response on the same tiny little Asus Eee using google maps. And the maps look better. At least I can tell the difference between different types of paths.
Here is an example:
And using http://ja.is/kort
(yellow pages app), which uses the same data as the garmin map:
This map is smoother/faster/looks better in a browser, than a dedicated Garmin GPS application. If only I could cache ja.is tiles and connect them to GPS.
Ok, I'm done ranting.