Hello,

Each individual will have to do their own evaluation concerning what an application is worth to them. For some that absolutely need some of the specialized tools that Spaceclaim has it may be worth ten times the cost of MoI. In my experience Spaceclaim is a good conceptual modeler but is not a great organic modeler. I started with SU before they were consumed by Google, and while I appreciated the ease of use and the push/pull way of doing things it didn't take me long to run into workflow roadblocks that got me looking at MoI in a serious way. It will take a bit of rewiring of process in the brain to appreciate how to create models, but in my case the journey is worth it.

If you're worried about not being able to model faster than the idea escapes something I like to do is have a bunch of scrap paper around and keep sketches. I also think sketching programs like Artrage are great to quickly capture ideas and then import those for refinement in MoI. If you have Rhino something like TSplines or Clayoo might work well for you. For advanced surfacing I use VSR in Rhino, it saves me from dealing with Autodesk (Alias) and it fits my requirements.

I think what cannot be discounted is the great assistance and education that is provided by the creator of MoI as well as the MoI community. That kind of support and attention to the user base is quite rare in the computing world today.