To Read or Not to Read?

City of Fallen Angels (The Mortal Instruments #4)
It’s a little cliché, but we’ve all faced this question at least once before, right? Here’s my dilemma. I recently finished City of Glass (Mortal Instruments #3) by Cassandra Clare. I enjoyed the first 3 books in the series, despite the fact that Clare’s books have been the subject of a ton of controversy. I know, I know — Clare has been accused of everything from ripping off concepts from other authors to extending the Mortal Instruments in an attempt to further line her pocket.  Now, I don’t want to say I don’t care about either of these things, because personal integrity is important, especially when readers are paying good money to read your work. As readers, we deserve an author’s best effort. But, there’s still that one little niggling voice in my head that wants to move forward with the series.
City of Fallen Angels, book #4, has received some glowing reviews and some, well, downright hateful ones. All things being subjective, I can’t decide if I should shell out the money to read the fourth book. On one hand, reviews of disappointed fans that felt the series took a turn for the snore-worthy (and many of whom felt cheated by a thin/disorganized plot) carry a lot of sway with me.
Why read a book if it’s going to take a series I enjoy and wreck that warm, fuzzy view? City of Glass ended in a good place and the story felt complete to me. Do I dare continue to City of Fallen Angels and risk hating it like oh so many other fans?
On the other hand, knowing what I know, I still feel like I need to see it through to the end. Despite the terrible reviews and the likely chance of disappointment, I want to see where the story goes.  Call me a glutton for punishment, but I have this need to just know.
So I ask, to read or not to read the City of Fallen Angels?