At first I was a little skeptical about the quality of these, but after I got to see them in person I was satisfied. The room I used them in measures 4000x2500mm and 10 panels were enough for it. The only issue you might have with them is a paint like smell which will probably persist for a few days, keep the room well ventilated for 1-2 days and it's gonna be fine.
As for their acoustic properties, they seem to do their job pretty well, the difference is noticeable even by untrained ears. If placed properly they can be as good as way more expensive counterparts.