I took a quick look through the documentation as well, and was pleasantly surprised by the maturity of the features that it has. This provides pretty much all of the basics I think one would need to manage a medium sized store. One area I do think could be improved perhaps is in the internationalization; it seems to me that every product has a single string to be the description, a single string to be the title, etc. with no easy way to localize the text across different regions.
I also am curious about the pricing; the landing page mentions that you can get started for free, and "start building for free", but is there some component that costs money down the road? I don't see any pricing page on the website so for now I'm assuming it's 100% open source.