I have 2 of these IstaBreeze wind turbines.
Yes they work, but not as well as home made ones with wooden blades.
They have plastic - fibre blades but in high wind they are bending and hitting tower mast.
Once they cut such a way about 15sm from edges and still working.
I ordered new blades and put this thing working without tale. Working too but not with small wind. At least they can not hit tower mast any more.
I found also Y shape metal where blades connected, also bended. Probably made from chinese steel - metal also.
After 3 years slip ring failed, ordered new one from ebay and working again.