The Google Structured Data Testing Tool works fine for me, but still my star review rating will not appear in Google, I tested it out with one of my products at: http://www.himac.com.au/products/skid-steer-rock-bucket
Note that through my workplace's Shopify site we do not have any prices displayed as use it for a quote request style site. Someone did mention to me that may be the issue for Google, but is not certain.
Anyone having any luck with the Shopify Reviews app?