Not "bad" that you haven't read it, but I'd say it's definitely on the list of "required reading" for Batman fans. I know Nolan gets a lot of flack for straying too far from the universe of comics, but one especially blatant nod to the source material was...
...that Bane, literally breaks Batman over his knee like a twig. Besides surface details like the location and the costume designs of both characters, it is ripped straight from the comics panel. Nice touch.
Ive just never read it. Its quite odd, because the comics I have are;
Legends of the dark knight issues
1,2,3,4,5,6,7,8,9, 10,11,12,14,15,16,17,18,19, 20,21,22,23,24,25,26,27,28,29, 30,31,32,33,34,35,36,37,38,39,
40,41,42,43,44,45,47,48,49, 51,53,58,61,62,63,64,65,66,67,68,69
70,71,72,73,74,75,76,77,78,79, 80,81,82,83,84,86,87,88,89
90, 101,102,103,104,105,106,107,108,109, 111,112,113,114,115
137,138,139,140, 141, 163,164,164, 191,192,193,194,195,196,197,198
201,202,203,204,205,206,207,208,209, 210,211, Annual 2
Batman Detective comics 2012 issues 1,2,3,4,5,6,7 first prints
Batman Year three issues 1,2,3,4
Batman Broken city issues 1,2,3,4,5,6
Batman as the crow flies issues 1,2,3,4,5
Batman Dark Detective issues 1,2,3,4,5,6
Batman Dark victory issues 0,1,2,3,4,5,7
Long Halloween issues 10,11,12,13
Novel-wise;
The Long Halloween, Dark Victory, Haunted Knight, Gotham by gaslight, Batman Black Mirror, Batman and the Monster Men, Batman Cacophony, Batman Widening the Gyre, Batman versus Bane, Batman Under the hood volume 1, Batman under the hood volume 2, Batman Jokers last Laugh, Batman the man who laughs, Batman Arkham Asylum living hell, The Killing Joke Batman Year one, Batman year two, Batman court of the owls, Batman a death in the family, batman vs punisher, The Dark Knight returns, Batman Earth One, Hush volume 1 and 2.
yeah sorry for the long post. But out of all of the comics, Knightfall I have never read!