I watched S1 when it came out in 2014, was somewhat annoyed by the Hieronymus Bosch name gag (but the actor is named Titus Welliver, so… ludicrous historical names all around), all the jazz (not even music), and some of the inappropriate workplace relationship bothered me, but it was a competent murder show. Little scattered in plot, personal drama, and side-plots that go nowhere.
Picked back up S2 and now working thru S3, and I'm more interested. The jazz is sometimes overbearing, especially when smug asshole Bosch preaches about how great vinyl is, or how every restaurant he goes to is "best X in L.A.", he's a super punchable prick. He's like House or Sherlock Holmes without the genius or charm. As a villain, he'd be fantastic. As a protagonist, he's much less charming than Dexter Morgan or Walter White.
But J. Edgar the partner (Jamie Hector, aka Marlo Stanfield on The Wire) and other competently-acted characters (several also Wire alumni), and better plots and writing, make up for a lot.
S1's a cold case murder. S2 is more of an LA Confidential thing with a murdered porno producer and hot blonde wife named Veronica (not Lake) as a film noir femme fatale. S3 has a couple parallel veteran murder stories going on; I assume in the books these are Vietnam, there's something about how they're written that doesn't fit the desert war that never ends.
★★★½☆ solid but rarely amazing.