It is a good program (*), but I am not sure that it is especially worth buying it. What program do you currently have?
As free software there is Media Player Classic which works fine (there is also VLC, though that it is a little less easy as it does not allow frame-by-frame playing and the pause is not immediate)


(*) except that on my previous PC it was unable to use the digital output, that's why I started to use MSIDVD and then WinDVD (which are both the same, I got these bundled with hardware that I bought)