The room facing material is very nice and high quality, with a ruggedness almost like denim but much softer. After installing two panels I immediately noticed a decrease in outside noise. The loud trucks that do lawn mowing at midnight near my house are about half as loud as they used to be. The blackout layer is very effective and my sleep quality went up as a result of decreased light.

If your panels don't fit flush to your window due to space constraints there will be some light bleed at the top. For me it isn't a big deal and looks nice anyway.

You can hook your rings to the two parallel threads instead of connecting them directly to the panels. It's worked for me so far with seven rings for each panel.