Here is my 2 cents; I started out as a graphic designer/prepress tech and used a Mac since about 1990. In the last 5-10 years, I transitioned from that to product and packaging design. The last couple of years it has been working in Rhino all day. When I first started using Rhino, I was doing so using it inside of Bootcamp on a Mac. I quickly got tired of switching back and forth between Mac and Window and migrated everything to Windows (Adobe CS, Suitcase, KeyShot, etc.), which was a much better workflow. Once I was totally working in Windows, I then got tired of the hassle of dealing with Bootcamp and maintaining 2 operating systems and left the Mac altogether. I was a diehard Mac fan for a long time, but the practicality eventually won out and the workflow has been great.
I would highly recommend (whether Mac or Windows) that you start out with Rhino on Windows. One of the great things about Rhino is the ability to expand it by using plugins, which I use several, and that just isn’t available on the Mac version. There is also a ton of information available for learning Rhino and most of it is geared towards the PC version, so it would make it much easier to follow and use, if your using the same version.
As far as Rhino or SolidWorks, it does depend on what you’re going to be doing. As a packaging and product designer, I deal mostly in the conceptual aspect of development. I come up with a variety of options, rather quickly and they are presented to the customer as concepts, which is perfect for Rhino. Once a direction is narrowed down, it goes into engineering/CAD/tooling where it’s developed on a technical level and they are using SolidWorks. For what I do, I’d hate to use SolidWorks, but down stream, Rhino wouldn’t be the right tool for the job. There are some types of jobs (organic shapes and modeling) where I’ll actually create the parts in Rhino and they will be imported in SW for production, because Rhino can do it better. So it depends on the needs that you have.