I liked everything about this program, it was easy for me because you can get used very quickly as well since there are so many tutorials online that make using of working model simple enough without having any problems at all! Nothing really bad but maybe some people may find things like when they first use them confusing or difficult in getting their heads around how certain aspects work (or don't). This software has helped us out tremendously throughout our design process especially where we were dealing specifically within mechanical engineering departments such as product development/designs etc..