*DO NOT USE IF YOU HAVE MULTIPLE VARIANTS* *YOU HAVE BEEN WARNED*
maybe this app is great for some stores (or those who have few products) - but I have thousands of unique items and this app is the absolute worst for synching with google. You have to MANUALLY add each variant (color, gender, new/used, and size) - which you have to do via a CSV. the kicker is that once you do this - and upload the CSV there are so many glitches that you receive really descriptive errors such as "unknown can't be blank" or "domain not registered" - all of which changed once I edited the CSV (I followed the taxonomy of a successfully published item, and when I re-uploaded the file, even that specific item returned an error - and it remained unchanged)
If you joined shopify with inventory - this app will cause you more pain that any thing else. And sadly, its an app you need.