They are using a Wordpress free site instead of hosting their own site, so that seems a little suspicious. They also didn't have great screenshots of their interface, so I would steer clear of them.
I would recommend purchasing your theme from a place like Creative Market (www.creativemarket.com) because they provide certain protections to their customers and a lot of the sellers there provide support for their themes. It's a much safer place to buy from.
Really? The only chatter is that which you've tried to start in two separate threads, here and at https://community.shopify.com/c/Shopify-Discussion/Does-this-really-boost-your-store/m-p/530826/high...
Then, on this post (https://community.shopify.com/c/Shopify-Discussion/Over-200-visitors-a-day-but-no-sales/m-p/530820/h...) you talk about how it "helped [you] tremendously."
Shady. Very, very shady.