The new font makes it 2% easier on the eye, but hyphens (for me anyway) make it 10% harder on the eye so it's a net loss. I read slower with hyphens so I would prefer not to have them. But I'm sure Amazon knows what's best and will not give me the chance to choose if I want hyphens or not.
I use larger font sizes, so the change to not have such huge spaces between the words is better for me, but please give me more font sizes! I usually need a size a little bigger than one of their more reasonable sizes, but the next size up is over twice as big. Amazon could also have just let me choose to have left justified which would fix the problem of too much spaces between words anyway. It would also look better than the print screen from the page linked to in the first post. One line has two partial words only - the end of a hyphenated word from the previous line and a hyphenated word continued on the next line. That looks worse than no hyphens and left justification would look.