Out of fear of spoiling the series I'm going to write a review of the whole series together, but unusual for me, I also intend to review the books individually in upcoming posts rather than just together.
First, I should point out that it is odd and rare that an author, who does not write young adult novels, children's books, or graphic novels to have written so many books (in-Universe chronology) in order. In the Legends series, only the start of Michael A. Stackpole's X-Wing Series ties Drew Karypshyn's four in a row here with the only book preceding these being The Old Republic: Annihilation. I think that this occurred solely on accident because there is such a large chronological gap between them. Darth Bane: Path of Destruction was Karpyshyn's start in the Star Wars Universe (and by total coincidence is also the last novel that I actually read, rather than listened to [I have read other books, just not fiction novels], which was shortly after it came out).
Next, there is another odd pattern that starts with this trilogy is a lengthy focus of books on the Sith and Sith Lords as main characters (at least for the audiobooks because there is at least one novel in the timeline that was not turned into audio to my chagrin). After this set of three books there are two more that focus on the Sith, Darth Plagueis and Maul: Lockdown and there there is only a one book interlude before the next Darth Maul book, Shadow Hunter which end the Sith focus.
Now, on to reviewing the series [possible spoilers ahead]. Overall my feelings about the series are mixed, but generally positive. There were questions that I had hoped would be answered that were not- mainly after Bane establishes the Rule of Two, how did the Jedi come to know of it? Having recently played through The Knights of the Old Republic game on the iPad it was surprising to me to find how many cross-references there were. It was also awesome to see the establishment of the Rule of Two, even if the leak to the Jedi went unexplained. I have also had the impression that the plan to take over the Republic was established about the same time as the Rule of Two and was a long-game, but only minor hints of that plan are shown and it seems to be much more circumstantial. Overall, the pacing of the books and the series as a whole is good. The training of Bane's apprentice Zannah was a delight to see, although her lack of courage to take on her master and the way the series ended was a tad disappointing. The other big let down of the series is that it is painfully obvious throughout that it was not originally intended to be a series/trilogy- it worked in the end, but would have been alright as a standalone novel. More details on these thoughts in my individual reviews of each book.
Reviews of each book in the series:
Path of Destruction,
Rule of Two, or
Dynasty of Evil.