Upside to reading many books at once:
You make weird and interesting connections between what people say — allowing you to *amalgamate the different ideas into something that is uniquely different.
Downside to reading many books at once:
You sit around wondering who the heck said that thing. You know, that thing that you're pretty sure is relevant to what you're writing a blog post about, but you can't remember what it is or where you read it.
Yeah, I can pull "amalgamate" out of my cobwebbed man brain, but I can't remember what the heck I read yesterday.
Good times.