Le Carré isn't (just) a thriller writer, he actually has literary substance and style. His books are subtle and complex. If what you want is action and people jumping out of planes and all that kind of thing, you aren't going to find it in Le Carré. If you want irony, depth and an understanding of how espionage actually works, including the utter corruption and cynicism of that world, then he's your man. The Spy Who Came in From the Cold is one of my favourite novels of all time in any genre. Of his recent work, I really liked A Most Wanted Man.
His son, Nick Harkaway, is also a fantastic author, albeit in a very different genre (the new weird end of science fiction).