Your best bet is to play around with all the features and find one that best suits your driving/area. The Auto is a mix of highway and city. As for the radar/speed check, it is that way when I go by them. The thing is cops can adjust there radar to close range or up to a 1/4 mile distance. Or they can just flip it on when they see you get near them.
My cousin works for the Sheriffs Dept. He gave me all the Info on using his radar. He wanted me to test mine out with his car once when he was in the market for one, but we never did. I told him just buy it, it works great. I haven't had a "speeding" ticket since I owned it(knock on wood).