I'm guilty of it, you're probably guilty of it - I buy books based on the cover. Look, I know. I'm a librarian. I get it. That's not HOW you should choose a book. There are better ways. I'm also guilty of NOT buying books based on the cover, and missed out on one of my favourite series for years because of it.
This book took me forever to read. I read it pretty much a chapter at a time (which is very, VERY unlike me) and it took a solid month for me to finish. The thing is, it's not because I didn't like it. I get why there were mixed reviews of it, and I get why there was a love/hate relationship with it a lot of readers seemed to have. It's a bit of a slow book, and very layered - you need to pay attention to a lot of subtleties, or you're just going to get bored.
I, personally wasn't bored. I am firmly on the camp that this is one of the best books since ever, and I'm planning to recommend this book a lot, to (almost) everyone. The imagery of the Circus was beautiful and made me wish there was something like it - it brought back that childhood memory of the fantasy and whimsy of the Circus' we went to as kids, the same Circus' that going to as grown ups lost a bit of their magic to adult eyes. The book is high magical realism and I would say even if you end up on the not liking it, it is well worth a read.