I'll answer your questions first, these trains are really luxurious when it comes to coaster trains. They are really the Rolls Royce of coaster trains, but they're much heavier than PTC trains, so they can tend to be more rough, but IMO it means more fun! The trains won't work on coasters like The Raven, but I'm not sure. The only coasters I know that use them are the Thunderbolt (Kennywood) and the Blue Streak (Conneaut Lake Park) and their track designs are rather "sprawled" out, meaning that the trains can't handle tight turns like The Raven.
Unfortunately, NAD has been out of business for a long time now and their trains are truely gems. Hopefully the parks that own these trains continue to use them.