I use video tutorials and agree that they're "good for getting an introductory overview". Specifically I think they're great and useful for gaining knowledge on any given topic regardless of how advanced. Videos can be just as in depth as books, depending on who makes the video. That said, I'd rather watch videos that are 5-10 minutes long and give a great explanation of specific topics as opposed to watching a 2 hour overview lecture on video.
For instance, I don't want to watch "php in a nutshell" for two hours. I'd rather watch "intro to if-else loops" or "advanced if else statements" for 5 minutes and then decide on what I want to watch next just by reading the title of the video.
I treat videos the same way that I treat books. I don't want to spend hours and hours with either one and would rather cherry pick my content for what I think i should do next - it's even better with guided content that has an outline structure or table of contents to save me some thinking - of course, if I don't care about loops, I'll just skip that series altogether.
Now, of course, books do have their place. I find them irreplaceable as reference material - imagine using windows-grep and searching a folder of pdf's on a specific topic.
Still since the book and the video might contain different information, It's really a matter of which particular resource would be easiest to learn with for your particular case. Sometimes i can't find 'good' video tutorials on a topic and I have to switch gears and go to books or some blog post with a tutorial.
The information can come in all sorts of formats. It's the authors delivery and your own circumstance that make one or the other attractive.