HHHHmmmm. i don't think that can be answered definitively as they both have there place. Sure there is an overlap, they both (can) teach better magic and they both (can) teach new tricks but one is better for some things and the other better at others.
DVDs
- Good at showing perfrmance skills
- Good for reviewing a particularly tricky sleight that sometimes from a book you don't quite get what is required. However once you have seen it performed on the DVD - the book becomes important again as it is now easier to practice from the book description.
- Good for seeing some of the Magic greats performing
Books- More portable, can be taken to work, the park etc. to make much more flexible practice sessions.
- More pleasing to own (imo).
- In many cases a book would contain much much more information than a DVD, including a lot of incidental material. Take the "Card College" books for example. You start off with a history of th eplaying card. Then look at exactly how much information is in each book. How long would a DVD have to be to cover it all? or compare the amount of information in Bobo's to that of Ammars Coin Magic DVD 1.
In short they both have there place. Given the choice of one or the other I would always say books, without hesitation, but then also I wouldn't be without the DVD's I own, and I look forward to buying as many as possible.
Maybe a good comparison would be Scott F. Guinn's "Great Scott it's magic DVD and the similar book. I love the DVD. I know that the audience isn't great, and that some of the videoing was dodgy but it is still a DVD I will watch more than a few times - as I enjoy watching the man perform, and they are great variations to some classic tricks.
The book - also being ring bound - isn't as astheticsally pleasing to own as most books, but does contain a lot of good tricks with well documented explanations. For practicing the tricks I would always use the book.
RRTCM was great - but I still wanted Kaufmans basic DVD to help with some of the sleights. They are too different to compare in this way.
so to summarise, it's not fair to choose. AND YOU CAN'T MAKE ME!!!!!!!