Dan Patterson is a voice of reason. I'll play the role of devil's advocate as I so often do: instead of differences, what about one important similarity? Both are vintage, if not outdated data models. There is no question they have served the industry well, but the modern feature class data model has evolved from both, and has a proven track record for flexibilty, functionality, reliablity, portability and so on. I cut my teeth on coverages in ArcInfo and while my hair has grayed and thinned out, I still have all those original teeth; give me feature a class any day!
That should just about do it....
