These are great!  I hung these in my daughters' North facing bedroom which gets a ton of light in the mornings/summer evenings . These block out so much light that my girls are sleeping in on the weekends and not fighting bedtime as much in the evenings.  I will be purchasing two more pairs for our other bedrooms.  Note: make sure you have a double rod if you purchase these to place behind pocket-rod curtains.  

Pros: Great value, light-blocking, easy to hang
Cons: N/A