I resisted for years, but bit the bullet with this last truck purchase, and found that when Traveling back and forth 500 miles to AR, and being able to stay on the station du jour the entire way without having to continually scan for something worth listening to every 100 miles, was worth the coffee money/month.
Particularly like the coverage, both in content (still love to listen to Car Talk) and in location.
AAMOF, Too bad cable TV isn't more like XM radio...