Ebooks all the way. Every single time. So much more useful, versatile, and much less space and resource consumption (cost and storage).
Take one book as an example. A Game of Thrones. Physical dimensions: 4.2 x 1.3 x 6.8 inches. Weight: 11.2 ounces. That's about a pound of weight. Ebook storage: 3.3 MB (though most books are under 1 MB). Print cost: $6.99 through $9.99. Ebook price: $4.99.
I can buy a 16GB thumb drive for less than the print book costs. That one thumb drive will store about 16,000 books and it weighs about half an ounce. Reading on the phone I already use and carry around with me is great. I can highlight without ruining the pages, I can copy and paste text from the file, I can carry most if not all of my entire library around with me in my pocket, I can read without anyone seeing the cover of the book I'm reading (helps with privacy and spoilers), and I can read anywhere as I always have my phone with me. No need to tote around a bag or a heavy book. Further, I don't need to select one book to read for a given day if I know I'll be out. I have all my books already on my phone.
There's nothing inherently appealing to the physical artifact that is the book to me. I'm not a fan of the dust, the must, the smell, the rough or decaying paper, the substandard glues, the paper tearing, the coating peeling off the cover, the spine breaking, the cover curling, the bleed through of a highlighter, the storage space required, nor the physical effort of boxing up and moving house with hundreds of volumes in tow. No thanks. Slip a thumb drive in my shirt pocket and I'll be carrying more books than I could ever hope to read in a lifetime.
My interest is in the content, not the container.