Better than I imagined! Its ability to block out light is very impressive. I am giving it a 4 star review instead of a 5 star review due to the lack of options in relation to drop size. 

My window is above a radiator and a smaller drop size would be perfect to help avoid covering the smothering the circulation of heat around the room. The range of sizes available were very limited. If the size was perfect I would give it a 5 star.

For now, I will try to adjust the drop size myself.