Is there a comparison between the 3?
Moi - Rhino = Nurbs so voluptuous curves - surfaces - volumes / Su = Surface Polygonal Box Modeling (can be subdivised by plugins but artificial :)

Can MOI work with Processing language? Not aespecially

How does it work with a Interior Design type workflow? Fine as long as you don' t make organic modeling like pushed human anatomy!

Does it have better rendering than "native" SU render?
Till now you have a native work Light rendering so better than SU in certain aspect (but not photo realistic and no project shadows, no texture)
You need an external render for that! A free one like SimLab Composer Lite (max 1920 * 1080 can be a start! :)
http://www.simlab-soft.com/3d-products/simlab-composer-lite.aspx