got them for my home studio to use as first reflection point absorbers on side, front and back walls to create a RFZ in my small studio as I don't have time or space to install heavy and thick rockwool panels and I wanted to ensure using a non-irritating material. they are very useful. they don't emit any fibers or any odor which is great and they are quite light and easy to install.
In terms of acoustic performance, they do quite a good job taming the highs and meds and even some lower meds, I verified the results using acoustic measurements in REW with a measurement microphone and there is indeed a good reduction in flutter echo and reverberation in the room. they're a bit expensive compared to cheaper foam solutions but do a much better job than foam.