I was given a couple, I don't play them that often...but yes agree they are good when you need a minute. Repetition is the key to teaching children/babies many things & the dvd's repeat everything so I do believe somewhere along the line they would prob pick something up that they don't see at home often IYKWIM. Some are better than others, I didn't think it was too interesting...but they are for kids not for adults.
I was also given a music CD that my MIL swore by & said I should play to settle to sleep. Nothing at all settling about that music I must say. DS hated it & so did I.
I don't have any expectations on the DVD's they are a "sometimes" thing. Sometimes for a break, sometimes its raining & we've read every book in the house, sometimes DS just wont settle. I too believe in reading to them & so on but that wasnt the question raised.