I've read parts of volumes 1 and 3. This book is awesome if you have the time to digest it, but you get faster results from other books that are easier to read, like Cormen's Algorithms.
If you are expecting TAOCP to be an Algorithms textbook, you're going to be severely disappointed.
Personally, I find TAOCP to be highly underrated. I find Knuth to be an utter joy (and just yesterday, greatly enjoyed watching the video of the 16th Annual Christmas Tree lecture.)
CLRS is a great Algorithm textbook, but it's not the place to go to find why there is a Pi in the formula for the approximation of Catalan numbers.
But I'd be interested in knowing what books you refer to as far as giving faster results beyond that(TAOCP is dense which I'll agree makes it a difficult read). I've never found a book that covers the same information as TAOCP and while I hated every second of reading it when I was being forced to do so I have to admit the knowledge has served me well
Personally, I still think K&R is the best CS/programming book I've ever read.
(TAOCP is wonderful but I think the great majority of potential readers would be better served by Cormen/Leiserson/Rivest[/Stein]. But when you really need Knuth, nothing else will do.)
"Elaboration of these ideas [2-3 trees, and a way of representing them as binary trees -- gjm] has led to many additional flavors of balanced trees, most notably the red-black trees, also called symmetric binary B-trees or half-balanced trees" ... followed by a list of references to places where these other sorts of tree, including red-black trees, are discussed.
So, indeed, you wouldn't turn to Knuth for "red-black tree magic".
What it does do is give you depth of knowledge. It helps you to understand the part of the computer you've never even thought of if Java is the first language you ever learned.