many out there and there alot of people that are fans to like GARMIN and other popular brands, so it becomes choice and price... the rest is what they may do but at the end of the day we only use a couple of features..
http://www.navman.com/
i have them, i have used them for years, free upgrades when road patterns may change, flash card memory, so you may load up any state or country you want..
i have used it in florida during bike week ( great battery life) to get around some of the trips i do and have used it on my bike here when i find or get lost on a new road, i hit the mountains, get lost and just hit the home bottom!! and thats that!!! place it on the cradle for the car with car charger and im good to go!!
good luck! its all about choice!!