Where? The question should be: WHEN???
Yes, WHEN would be a great question.
However, I prefer my books printed. I don't have a laptop with me when I go gaming. I have a nice desktop tower for gaming but there is just no way for me to bring my desktop with me when I go to a friend's house to game.
I love being able to take a physical book with me to sit to read, or to lay in bed to read. If there is a chart or table that I would like, I photocopy it and put it in my GMing binder for quick access.
I don't want to buy a PDF only to turn around and to print it all out so I can read it or access it. That would end up costing even more in paper/toner cartridges and then I would have stacks of loose paper hanging around. I had the chance to buy a couple of the books on PDF and it's just not worth it for me. There are at least 4-5 Shadow World companions I would love to have, but I still can't bring myself to pay almost the same price for PDF vs. printed just to end up printing the pages anyway.
As a side note, having the printed material in Game shops on the shelves is better advertising for ICE and RM. Who walks into a Game shop and asks "What's new on PDF? Are there any new game systems out there that I've never experienced that are only online?" Walking into a Game shop and seeing something "new" or different on the shelf, gets the person to pick up the book and to flip through the pages and maybe get word of the product out there. If the new material is only on PDF, online, then only the people already in the circle know of it and will download/buy it. Without the physical presence on the shelves, the new, fresh, curious, younger market will never be tapped as new clients unless a veteran of RM somehow piques their interest.