This is one of those love it or hate it books. I certainly didn't love it. At 800 pages, the hardback version makes a great door stop. It was so long I had to take breaks from reading. Long breaks. The concepts, themes, history, whatever were lost on me. Every time I thought I had grasped the flow of the story, it would slip right out of my head. It was also historical, and I hate those.
But in a way, I didn't completely hate it either. I say that mostly because after two attempts I couldn't get through the book and maybe the best part, the part that brings it all together, was at the end. All those reviews of people saying the book is absolutely groundbreaking and amazing give me pause.
So if it boiled down to a recommendation, that would be a no. But if you are into that kind of stuff and you read all the reviews with increasing interest, then give it a try. Jonathan Strange & Mr. Norrell by Susanna Clarke. And good luck.