As a collector generally I like well made books.
So a good looking hardcover is great but a well made softcover is good as well. The Japanese really nailed the art of soft cover books.
I like to read on a Kindle because you can better underline and collect important information. But it doesn‘t work well for graphics.
Still a digital edition is a must for me. I like to buy the audio book version as well and use „whispersync“ for my bike rides.