Quadratic Diffusers


I'm looking over the GIK Gotham N23 5″ Quadratic Diffusers. 

Anyone have any experience with these or similar? Care to comment?

What did you think of their construction, hanging hardware, aesthetics, effects on the sound, placement ease or difficulty?
https://www.gikacoustics.com/product/gotham-n23-5-inch-quadratic-diffusors/
hilde45
Thanks folks. Two interesting options. I think I'd rather find plans and save the money on the kit by buying it all myself. If that would work out, $$ wise.
Hilde45, I am not a fan. I think if you use the proper absorption in the right places diffusers are an unnecessary expense. You can get an entire case of acoustic tiles from the Foam Factory for 25 dollars. Something like 30 tiles. They come all compressed and you will look at the mess thinking you made a big mistake. Just unpack them and walk away. 24 hours later you will have a stack of pristine tiles, they inflate like automatic balloons. I use the 4" tiles. 
@mijostyn I was already given a couple of diffusers which are doing a great job. I'm interested in adding a few more given the current evidence I have that they work. I'm thinking about a diffuser able to operate in two dimensions.
The Quadratic Diffuser has a limited range (bandwidth) but do add 'dimension' to room treatment.
No need to go overboard though ... narrow down tour need then apply a suitable application.
The vertical slats (quadratic residue) can be combined in a hybrid diffuser / absorber like some of the GIK products.