You'll be fine with it. All Harmony remotes are awesome. I had a 720 for a few years and recently upgraded to the One after my 720 was getting a little too worn out. The is functionality is pretty much identical, the One just is more ergonomic and has a nice charging station.
Best part of the harmony remotes is that you can add all your devices and setup "Activies" to switch between watching TV, playing Xbox etc and customize any button or activity action.