When this aired in 1987, I taped it but rapidly lost interest.
After reading the novelization, I re-watched this recently after discovering torrents of it on 3 DVD's at conspiracycentral.net. It was(to me)a very interesting concept. I liked the archetypes of the three main characters, and a few of the supporting cast. Unfortunately, it was undone by a horrible pace and far too many cardboard characters. Really, we didn't need to stop for 60-120 seconds every time someone says something "important", just to play dramatic music over a montage of people looking pensive.
At heart, I found it an interesting exercise in paranoid fantasy, undone by horrible direction.
For those of you folks who have wished for a modern version of this miniseries showing America under Sharia law, pick up "Prayers of the Assassin", a novel by Robert Ferrigno. It's even more unreadable than Amerika was unwatchable, but plays to paranoids just as well as this. I've seen it on a number of clearance tables at bookstores, so you folks shouldn't have much trouble getting a copy.