[Penforhire]

I think the character introductions matter, making it useful to read them in the order he wrote them.

If you read "Best Served Cold" first then you have less understanding of the one who heals Monza (who his master was and more but ... becomes a spoiler). Vitari would also have no reference. Joe is still quite stingy with his background explanations. Same for how he introduces Caul Shivers in earlier books but Best Served Cold is more his origin story (and he is still only incidental to the protagonist!).

If you read Red Country before the trilogy you will be too unsympathetic to the captain of mercenaries, Cosca. You won't have any history with Black Dow or know why Gorst is so tortured by his loss of station.