I would pay good money to be able to use SU, unfortunately I am one of those people who have no 3D imagination or conception, call it what you will. After repeated attempts and viewing all the videos etc I still cannot use it. Delta Cad I found easy, the only issue for me is (or was) the ability of it to handle metric and the scaling was hard to understand IIRC due to the metric shortcomings. Mind you it was quite a few years ago now so it may be improved.
Chris
Everything I like is either illegal, immoral or fattening