I just got the free Amapi 4.2 ... I haven't done much with it but I will say that I was surprised when I registered that I was immediately contacted and offered help locating tutorials and offered help using the product. Customer service means a lot to me. I've no idea how it compares to other modeling programs. I understand Amapi 5 is available free on a CD in a computer magazine but I haven't found any yet, but I am very impressed with how responsive my contact was to my questions.