I have mostly hard copy: soft cover, hard cover & magazines. I am an Amazon junkie, especially the older used publications you can get for a few dollars, often less than a new magazine. I have an Ipad, but you have to watch what you buy. First of all, you can often get a used one for less money. and second: I have made several One Block Wonders and have her first book. Even tho I found the pattern for the open cubes on line, I decided to buy her 3rd book from the Kindle store. When I got it, I was surprized to find that it was black and white. I couldn't decipher many of the illustrations and finally had to get a hard copy version. The kindle does not have color capabilities, but I had purchased a couple other quilting books from Kindle and they came across in color. I went back and read the info on the OBW book and the other color quilting ebook I purchased and nothing in the description indicated whether the file was B&W or color. A query to Amazon went unanswered.
Oh, I also have binding equipment, so if I find I'm using a book or magazine a lot, I will rebind it with a spiral spine.