In my case, I'm still quite happy with the Nav system in my wife's 2009 Rav 4 actually. It works as intended to this day. It's missing some fanciness, but I'm just not about the fancy.
The issue is updating the system with new maps. My car's nav system is now about two years old and I find about 1 in every 20 addresses or so it doesn't recognize.
Overall I do feel built in nav systems offer the best experience, I just wish car manufacturers could figure out a better update process.
Overall I do feel built in nav systems offer the best experience, I just wish car manufacturers could figure out a better update process.