I’m reading them in the author’s recommended reading order and I’m currently up to The Vor Game. While the first Cordelia books are decent the Miles books are real page turners so far. So if you were put off by the cheesy looking covers like me, give them a go!
I liked the first two (about Cordelia) better than the Miles books in some ways. He’s just a kid, she’s more interesting in a lot of ways.
That said, I think the best bit of the whole series is the Miles-focused novella The Mountains of Mourning.