What was the most difficult read you've ever come across?  

I'd agree that the Quran is one of the more difficult books to read, if only because the way the verses are structured; the language used is very flowery and roundabout. It's one of the few books I gave up after reading a few pages.

Another that I stopped reading was Sense and Sensibility. For such a title, the language made no sense to me.

You might have read some archaic or literature preserved translations of Quran.
You may try reading some other english translations of Quran. First know that Quran is the words of God in his own words, revealed to prophet Mohammad via angel Gabriel based on the events and development of the new growing society during 23 years.

Try three english translations together
http://www.usc.edu/dept/MSA/quran/

For translations with detailed explanations see:-
http://www.tafheem.net/main.html

Cheers