I agree with the last poster!.. It IS worth it and I can't imagine my TCH without it. We have used it a number of times already and it is definately a great thing to have.
Only the newest places, Points-of-interest, roads etc. are missing. If you take a little time with it, read through the extensive manual, and begin to use it, you will love it.
I have a hand-held Magellan GPS but this is a whole lot better. There will still be times where the portable is the only option, but as far as automotive use, it is superb.
My wife discovered she can locate clothing stores in unfamiliar areas with it.. (This could be a bad thing, I suppose!).
I plan a long western trip in the fall, so will really try it out then.
FYI it is a DENSO system, (Japan) version 5.1 meaning 2005 version 1.