I have read the first omnibus, "Hawkwood and the Kings" almost a year ago and had a good experience with it, which I described in the post. Again, in "Century of the Soldier", it is hard to make a short description because these are actually three books, and the last one happening almost 20 years after the middle one. But I will make a presumption that you have read the first two books. In essence, there are two main lines. In the east we have Corfe, as one main character, with bunch of other characters, fighting against the Merduks who are once again massively invading Torunna. In the West, we follow events in Henbrion, King Abeleyn's fight to reconquer his throne, helped by wizard Golophin, and return of captain Hawkwood from the far West. And the last book combines these two plots in one, where our heroes fight against the might of the Second Empire, a militaristic theocracy empowered by magic (Dweomer) and werewolves (among other things).
There are several things that differentiate this series from other. There is much sex, especially at the beginning of the first book in this omnibus. Even though I remember some of it from first omnibus, it definitely wasn't so bold. But I was much more surprised by brutal and graphical description of was violence, especially Merduk's rape and plunder through Torunna. Battle scenes are also pretty graphical. Kearney sometimes use trick Erikson often uses: talking through perspective of unimportant character that is later not even mentioned again.
I also liked how Kearney doesn't follow the tropes. We have an uncommon romance between younger man who is one of main characters, and (much) older woman. When I think about it, all love and marital relationships in these books are, well, not very healthy. There is also much of nice ambiguous morale - Golophin and others have to choose the side; Corfe and his love to his "daughter"...
Another specialty of this series is its magic system, Dweomer, but also its coexistence with gunpowder and cannons. Nothing much new compared to first two books, but this is a solid part for Kearney. This is not a classical fantasy - it is a historical fantasy but with a nice touch of magic, maybe akin to Guy Gavriel Kay's books.
I like Corfe's part in first books (there's no Hawkwood in first book), and things got pretty heated up in second book (which I like better). But pace is too fast in occasions and changes come to abrupt, which results in sudden and not-so-solid resolutions. I would have appreciated it more if the pace was consistent throughout the books.