I don't know PressProof, but the Display calibration software costs more than an i1Display Pro (which I presume is the chuck that it uses). Better to buy an i1 Display Pro and the XRite software that comes with it (i1 Profiler) will do the job perfectly for you. Or you can use the very powerful ArgyllCMS freeware: it's command-prompt driven (so a bit complicated to use), but there's a GUI for monitor calibration called DispCalGui.
If you're really serious about color management then don't waste your money on display calibration only and go for an i1 Pro 2. Very expensive, but it will calibrate all of your devices.
Robert