There's been enough captures out there to know they work, well most of them. However, I personally would not buy one! Busted, rusted and failure is what I have seen and that's enough for me not to use that product.
Yumeya is a specialist aftermarket arm of Shimano and the quality is generally very good. Never had an issue with a Yumeya product however, I do find the protective coating on the new stock spools to be disappointing. I hope they rectify this.