I can't comment on whether or not the signs are accurate in this video, but having borrowed books about signing in the past and failing miserably to remember any of them, I have to say I've been very pleased with this DVD and the memorable way I've started remembering the signs.
My one-year-old can sign "nappy" (although I realise he's technically signing "change") and, tonight, I started reading him a little book about farm animals and as I soon as I sang the "I went to visit a farm one day" and did the signs, his eyes grew wide and he was completely absorbed by the book and the song even though he was very tired.
Then there's my 3-year-old: she has memorized all the signs and all the songs and enjoys practising them. There are times when even she responds better to signing than to words, such as "don't" -- which she pays no attention to normally, but when I sign it as well, she understands completely.
I do agree with other reviewers, that the viewing time is very short for the money. However, it does teach you, and for that, it's better value than all the signing books I've bought over the years.