If you are a designer, Rhino is the best way to go. The software allows you to create beautiful flowing surfaces and then EASILY change or experiment.
SolidWORKS is better for manufacturing and engineering. If the design is already done, then its linear (some call it 'anal') workflow is great for getting to a finished model. Using parametrics ('history-based') every dimension is input at every step of the way. This definitely helps when a change is needed after the model is completed, but many designers like to experiment with alternatives and build 'test geometry' to see how it looks ... which is not easy or what SolidWORKS was designed to do.
The best answer to this hot-button question was given to me by a friend who did the following:
- Use Rhino to design, experiment, and make it beautiful with world-class rendering engines like V-Ray.
- Then, bring the geometry into Solid WORKS for any shelling, bosses, or structural stuff.
Here's a cute little penguin I did with Rhino. As far as I can tell, this shape is close to impossible with SolidWORKS.