My oldest son got me this for last Father's Day - I confess I hadn't even noticed it existed. Unusual, as I have most of the Stephen King novels on my bookshelf: I think he's one of the most underrated writers of the last thirty years or so.
Having said that, this book is perhaps the first one where his techniques show through. One of SK's skills is that he launches into a sub-plot or even somebody's maunderings, and you get totally involved in that, until he jerks you back to the main plot. And you think, 'Oh yes, that was just a side issue.'
The thing is, when he's at his best, you don't even notice this is happening. But in The Outsider, you do. Or I did, anyway. Especially with people giving evidence: they wittered on about not very much before getting to the main point(s). All of them.
I was still gripped by the book, still couldn't put it down. Especially in the first half or so, where the mystery is laid out. In the second half we get caught up in SK's own tropes - no mean feat, that, to have your own tropes. As usual for a Stephen King novel, I recommend it as a read. Just perhaps not quite as enthusiastically as some (most) of his earlier books.