Not sure ...I had a Cobra a longtime ago it was the worst GPS I ever bought. The routes were way off you couldn't even use it. I threw it at sign on 95 and felt good about it! Seriously though not sure if they have improved or not. I have a new Rand and it just fine for me
I just got the 5" RM. My trainer had one so I knew how to use it. Not speaking from a lot of time using it. Onky about a month and a half but so far it hasn't done me wrong. Just make sure you update it when you get it. No telling when it was manufactured and no telling what roads have been switched around since manufacture.