I would recommend WIN-500. The interface is very intuitive, and Don Starr of Starrsoft regularly provides free updates for the program, and addresses questions and problems VERY well (he's DonS in the forums). In addition, as a premium (as in paid) subscriber to RadioReference, you can download systems directly into WIN-500. Also, many people on the forums have WIN-500 files they will share. You can't go wrong getting WIN-500, especially with the free trial.