[1] with over 25 games to play, a 60 minute demo is inadequate time to evaluate.
[2] Price of $19.95 is reasonable
[3] Download size of approximately 600+ megabytes requires a fast connection or a lot of patience.
[4] So far I've evaluated chess and it has some annoying qualities. Menus are non-standard and so searching is required to find the option needed. It isn't easy to switch colors. Apparently, it is necessary to just quit the application and restart. Several more what I would call quirky behavior for a Mac application
[5] This might be a good deal but with only enough time to evaluate one or two games I doubt I will buy.