I mostly agree with you, although my experiences with NDS have been positive (good route calculation in general, not always).

Re. alternative routes/ 3 routes; once you have set your route, you can go to "current route" (I assume it's something like this in english, my phone is set up in another language) and choose "alternative route". TomTom then calculates 3 different routes and shows you how much longer/ shorter/ quicker those routes are compared to the original route.

In general Tomtom NDS is very good. I agree that sometimes smaller roads are chosen, although that wouldn't be the most logical way to go. But you have to remember a lot of maps are drawn using satelite images. So sometimes a road is "misqualified"; it is given a better or worse rating then it actually should get.