I read this for the 2016 Challenge "Read a Graphic Novel" and my 11 year old owns them all (that are currently published, there is a new, highly anticipated one coming out later this year, I think).
Overall, I think I'd give it 3 stars. I was surprised by how powerful the emotions were, especially for a book geared towards younger readers. Part of me enjoyed being able to whiz through pages just by taking in images and minimal text. Part of me missed being able to decide for myself what the characters and things looked like. It was also kind of science fiction-y in a way that isn't instantly appealing to me.
HOWEVER, I recently was made aware of a condition that exists for some people who absolutely CANNOT think in images. I never knew this wasn't universal to the human race. So for all those kids who have a terrible time reading-and think it's more work than it's worth-maybe they have this inability to transform a description into a vivid as life image in their minds. Especially for that group of people, I think graphic novels serve a really great purpose.
I might explore graphic novels more in the future, just for a change of pace every now and again. I'll probably peruse through the rest of the Amulet series simply so I know what my kids are reading.