We've been needing a shade in a front room window for a long time and this was a good chance to tick that box.
I hate installing shades and these sounded intriguing. The target window is a casement, and does not have a deep box to drill any screws.
My main tip here is to measure carefully and read the listing for instructions. I picked the size that was recommended for my window. When I went to install it, it truly was extremely easy, even with the shallow area I had to work with. The springy mechanism keeps it in place. The roman shade style needs no cords, which I love, and the color is a kind of perfect neutral to go with just about anything.
Now, about the "100% blackout" claim. It's close. I don't need it to be 100%. But if you do, I would say your results may vary depending on the actual width of your window. The material IS thick and it will help.
Overall I think these are a good value for the price, material, and easy installation.