Yeah, even if you do not purchase and use it for PR renderings, the eval version (and its 800x600 pixel output) should be enough to experiment with your "products" - as for how they behave there.
They should more or less render the same way in Kerkythea then. AND I presume, the soon coming Thea Render would behave somewhat similar - although its material handling is said to be different, still Tomasz is the one who writes the exporter (as of Kerkythea's original su2kt) therefore there shouldn't be any issues with it.
I really wonder why V-ray hasn't been made to recognise alpha transparency yet. One of the most powerful rendering applications - and not only for SU but for several, other modelling soft as well.
BTW nice trees/shrubs again (what are junipers - trees or bushes?)