I think the rules and objectives are too complex for a casual player off the street. I have a number of free game now and then at home and still have not gone the full hog on any particular late DMD machine. The difference between paying and playing free is that you can experiment different shots without loosing lots of coins.
Now EMs and SS are a different kettle of fish. Their simplicity in rules and objectives is addictive and their ball play requires skill and determination, again extremely addictive.
