I prefer to have both.
It has been my experience that they often fill in where the other lacks.
I like text with step-by-step instructions (including illustrations of the steps) but often there is some small nuance that is left out that may be shown or explained in a video when watching someone actually performing each step. There may even be a small explanation that is mentioned in the video that tends to be left out when the instructions are put together. (Often, instructions are abbreviated for clarity, actually making the steps more difficult to follow...not enough explanation.)
When you have only video, it's very difficult to watch and perform the steps and stop videos as you are going. It's much easier to print out the instructions and follow it as you go. It's also easier to make notes on the printed instructions to help you remember essential tips from the video.
I like the way that Udemy has their training set up. While playing a video, you can make notes on the right-hand side about the video. The only other item I might include would be to be able to view the instructions & illustrations in another window at the same time, while taking notes or being able to write/type on the instructions & illustrations themselves...
I really enjoy having both for the sake of clarity in case something is missed in one, more than likely it's answered in the other format.
Just a thoughts and my two cents...
Thank you for asking!