I tend to agree with Michael, for presentations and design ideas nothing is quicker than SU once you have some good practice under your belt. The renderings you can produce when using one of the free renderers is amazing.
Granted you have to master working in 3D space, which is not an easy adjustment, I can tell you, but once you start working in 3D, 2D just seems so 'plain'.
We also use it to export 3ds files directly into Aspire, from our base model and it works perfectly. Granted you need the Pro version but for the small cost it's definitely worth it. After using SU for the last 4yrs or so I wouldn't be without it, at any cost.
Every rendering we put out to our customers is unique and changes can be made on the fly very fast. watch any of the hundreds of video tutorials online and you will be amazed. There are plenty people out there that think it's some sort of 'fly by night' kids program when they start comparing it to mega programs that cost tens of thousands but SU has a very big following of professionals that turn to it everyday for presentation use because of its speed and simplicity.
Tom in PA