I am a JD guy and I would stay away from the 60 and 70 series disk mower from JD. The cutter bar is a Kuhn bar. They where a fine cutter bar but they are 25 years old. The parts are available but you can easily stick $2-3K in parts alone if the cutter bar has issues.
Unless you are mowing a lot of hay I would stick with a simple sickle machine used. The disk machines can be a money pit to repair.