For original, in-depth, on-the-ground, and ongoing commentary on HFT developments in this region I recommend reading the "Sniper in Mahwah" blog(1). It gets a lot more technical, among other things. His posts are regularly featured here on HN(2).

(1)https://sniperinmahwah.wordpress.com/

(2)https://hn.algolia.com/?query=sniperinmahwah