I think his advice about writing is very good...specially if you want to write like Elmore Leonard...and if you want to trim out all the unnecessary verbiage.

I don't necessarily think it's the only way of achieving good writing, though. There are some other styles of writing that are good too, despite breaking some of his rules, and they probably appeal to a different set of readers.

For the kind of books he wrote, though, he's right on the mark.

(Just thinking of Amos's recent book "Beyond the Cascade". I think he does a number of things Leonard advises not to do in his 10 points of advice about writing...and I still think Amos's book is terrific, regardless.)