I-phone or android with Waze app.
Ditto.
Has the added benefit of identifying speed traps.
Waze is great! Route guidance, road and weather conditions, traffic problems, police locations, red light camera warnings. Continuous ETA updates are also a plus. Droid LG G3 with a Bluetooth is an awesome combination. Even if no guidance is used, it still gives all the info. Voice recognition for shops, dining, restrooms, coffee, etc., with “take me there” directions.
I’ve used Tom tom, but the touch screen was just lousy from day 1. Granted, that unit was from maybe 4 years ago or so but it was terrible compared to even the smart phones of the day. Wife has a new Garmin I got her for Christmas, works very well. I use Waze on my android smartphone if/when I need it. Other than those, I don’t know of too many other options. There are only a couple of players in the dedicated GPS realm and then you’re into a smartphone or tablet based app.