I think its fair to say that everyone has a preference when it comes to reading, what's yours and why? I personally almost exclusively read via physical books. Greatly prefer hardcover as I'm a collector and seeing a bent up or worn book makes me cry. Unfortunately, I can't always afford the hardcover or a great deal comes up (such as Barnes and Noble's $5 classic sale that happened recently) so I usually go with paperback.
Left to right and top to bottom? I do like a hardback, though, they are easier on the eye. Some paperbacks have really teeny-weeny fonts and I hate that! And on the flea market hardbacks are about 0.50, so that's pretty affordable.
Paperback for price, hardback for looks, and generally only digital when I can't get it in hardback or paperback. It's not that I have any intrinsic moral objection to digital, I,ve just never found a reader I enjoy using, or doesn't need electricity when there's none around.
In the bath tub. Aside from preferring to read while in the bath, I read physical books. I like hard back, but I don't mind paper back. I also have an eReader, but I can only read so long on electronics because it gives me a massive headache after a few minutes. If physical books ever vanished then I'd be out of luck.
If I'm just reading for pleasure, I love my e-reader. If I'm really trying to study something, paperback so I can make notes and scribble on it without feeling like I'm defacing something valuable.