He's said things that hit the nail square on the head, but he's also said some things that i disagree with, like his stance on RAW and JPEG.
The majority of people who read his site are in photography for family snapshots, which he recognizes as his target audience, which his advise is generally sound (again, for that audience).
I think that alot of people who say he's a joke don't understand who KR is trying to appeal to. Joke's on them because KR is laughing his way all the way to the bank.
Comparing a 5D MKII to a 3Ds is not something that's directed towards people wanting to take snapshots of their kids.
He took the 5D MKII image and blew it up to 24mp to compare it to the native 24mp image from the 3Ds and complained that the IQ sucked and the 5D MKII image was blurry. No ****, he enlarged it past it's 21mp native size.
He also had the stance that FF cameras were useless and a dying segment in the market and APS-C was the wave of the future. He changed his tone after Nikon released the D700.