I've read a few Craig Johnson "Longmire" novels, modern-day western mysteries you might call them. They're pretty good though not the typical western one might think of.
I've never read any Longmire, but modern day western mystery just doesn't sound right. I like my westerns set in the old west.
"Flint" by Louis L'Amour. I'll tell you what. He breaks every rule. There are scads of backstory. Lots of flashbacks. Loads of head-hopping. I'll be reading along and suddenly I'll realize there was a POV change, or I went into, or came out of a flashback, and I'll have to go back a few paragraphs to figure when that happened. He never uses any line breaks to signal the change, they just blur together. And yet, because of his writing style, and the fact that he's a damned fine story teller, I keep on reading because he's got me caring about the characters and its a fine adventure.