Our '04 Monterey did not have any GPS. I went through three Garmins all bought at places like Costco. The last one was like Roy's with the free US map updates over the internet. It has guided us all over the country and we've taken it to Europe twice. The Europe chip was about $40 and made a huge improvement to a driving adventure from Germany through parts of Switzerland, Italy and France.
Recent improvements to Google Maps on my smartphone are putting pressure on my beloved Garmin. The sole reason is the traffic calculations. Google knows where most smartphones are that are using Google Maps and something called Waze. Google's mainframe, sky and cloud computers can figure out the best route from A to B based on traffic clogged drive times. For example, there are three freeway routes going north and south for Portland, OR. Google Maps will keep you off the one with the worst traffic messes and put you on the better of the choices.
Another weird and newer function is that I can pre-flight routes and traffic on my condo/motorcabin computer. When I later turn on the smartphone Google Maps somehow seems to remember my most recent route inquiry and goes to work guiding me.
My Garmin has a traffic capability and gets data somehow from "sub channels" on FM radio stations. It works fairly well but not nearly as well as the current version of Google Maps.