MapPoint seems to be the easiest in that there's quite a bit of support.

Only place it comes short that I've found so far is that when I try to route 55,000 addresses in our area, between 3,000 and 4,000 of them aren't in MapPoint, some of which were constructed 3 years ago.

I'm able to work around it by entering longitudes and latitudes for that data but it just seems strange that a huge program like MapPoint wouldn't update data sets often.