Hi Dave,
I'm new to the forum as well, but have been lurking for a while now.
I use SU for the exhibit industry and have become very fond of the Maxwell plugin. It is really easy to use, but isn't the fastest renderer out there (the results are worth the time in my opinion though). I was using the free version for a couple of years and finally decided to buy a license for the plugin which really is not that much money compared to other options out there.
Maxwell is a nice all around rendering plugin, but for exhibits I am constantly on the look out for better ones. As an exhibit designer you might find issue with the lack of lighting options. Lights must be built in to the model by assigning emitter materials on to faces of actual objects (geometry). This produces very realistic renderings, but sometimes in the exhibit design world you need to just throw some lights in there with beams coming off of it to show clients that their exhibit will be well-lit. So I use Photoshop a lot to fake my lights.
Hopefully this helps.
Kyle